Premature ejaculation is one of the most common types of sexual dysfunction in men and is also one of the most misunderstood problems. Because the definition of premature ejaculation has not yet been fully agreed upon, the understanding of premature ejaculation varies from country to country and from region to region and from one historical period to another. In 1970, Masters and Johnson defined premature ejaculation as “the rate at which a man maintains ejaculation during sexual intercourse until he is able to satisfy the sexual desire of his spouse is less than 50%”. This definition did not define a definite time. In 1973, Obler defined premature ejaculation as “the maintenance of ejaculation in men within two minutes”, which regularly places great emphasis on an objective time. In 1974, the World Health Organization (WHO) defined premature ejaculation as “the lack of the male’s ability to regulate ejaculation at will so that orgasm is not achieved as desired”. This definition also did not have a specific time frame. In 1984, the DSM-III-R defined premature ejaculation as “ejaculation without desired penile penetration of the vagina or with minimal sexual stimulation”. In 1995, Ertekin defined premature ejaculation as “intercourse with ejaculation of sufficient duration to regulate the frequency of ejaculation to the satisfaction of the partner to less than 50%”, a definition that takes into account the experience of the sexual partner. In 1996, the American Urological Association (AUA) proposed a definition of premature ejaculation as “a condition in which one of the partners is dissatisfied with the latency of ejaculation, or in which the male is unable to achieve a sufficiently long latency of ejaculation”. Therefore, premature ejaculation requires a comprehensive consideration of the sexual experience of both partners. At present, it is basically defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV-R) issued by the American Psychiatric Association, which is: “persistent or repeated ejaculation before, during, or shortly after penetration with very little sexual stimulation, earlier than the person desires “. According to the late academician Wu Jieping, a leading urologist, ejaculation at 2-6 minutes of intercourse, or less, in young, healthy adult men is not considered premature ejaculation. For a man who ejaculates before his erect penis has time to enter the woman’s vagina, or just before insertion or just before entering without pumping, this situation can be defined as severe premature ejaculation without any dispute. If the man ejaculates 2 minutes after the start of sexual intercourse, it need not be considered as premature ejaculation. If the ejaculation can last more than 2 minutes but cannot be maintained until the woman’s orgasm, it cannot be excluded that there is poor coordination of the tacit harmony between the two partners. In clinical practice, a clear time criterion also seems to be important, and premature ejaculation can be regular in this way: “The patient has had a stable sexual partner for more than a year, normal sexual frequency, ejaculatory latency less than 2 minutes in more than 50% of sexual activities, and the duration of the disease is more than 3 months. The duration of sexual intercourse is also closely related to age, physique and sexual experience. As practical experience is gained and close cooperation between the two parties is enhanced, the duration of sexual intercourse may be prolonged. The length of the ejaculation latency is related to the specific environment of sexual intercourse, such as the first time a newlywed, a long time after marriage or long-term abstinence after sexual intercourse, the ejaculation latency may be shortened, which should be a normal phenomenon. In addition, the speed of ejaculation is closely related to the position of intercourse, the amplitude and speed of penile pumping, and the sexual response of women. Therefore, the definition of premature ejaculation has not been fully unified yet, and there are many non-pathological factors affecting the ejaculatory latency, which need to be further scientificized regularly through strict and reasonable research of evidence-based medicine.