The most common causes of frequent urination after intercourse are cystitis, urethritis, prostatitis, and parurethritis. 1. Cystitis: This disease refers to inflammatory lesions of the bladder caused by various reasons, the main reason is bacterial infection, women are more prone to cystitis than men, clinical symptoms include frequent urination, urinary pain, urinary urgency, pain in the lower abdomen and so on. 2. Urethritis: This disease refers to a kind of inflammation of the urethra caused by non-gonococcal or gonococcal infections, clinical symptoms of urethral pain, painful urination, frequent urination, etc., which can be spread through sexual contact, it is recommended to avoid sexual intercourse during the treatment period. 3. Prostatitis: This condition refers to a group of diseases that include acute and chronic inflammation of the prostate, which is usually associated with irregular sex, sedentary lifestyle, pathogen infection and other factors, the clinical manifestations of urinary frequency, urinary pain, sexual dysfunction and so on. 4. Paraurethritis: This disease is usually associated with pathogenic bacteria infection, such as Escherichia coli, staphylococcus, gonococcus, etc., the clinical manifestations of urethral attachment pimples, urinary pain, urinary frequency, urinary urgency, and so on. There are many reasons for frequent urination after intercourse, and it is recommended to go to the hospital to complete the relevant examinations and make a clear diagnosis in order to treat the symptoms.