Syphilis serofixation actually means that within 6 months for early syphilis and within 12 months for late syphilis, the serum still does not turn negative. In some cases, if the serum is fixed for a longer period of time, within 1 year for early syphilis and within 2 years for late syphilis, and still does not turn negative and the titer is below 1:8, it is called seroresistance. In fact, serum resistance is formed after serum fixation. There are several factors that may cause this condition, the most common of which may be due to irregular treatment of the patient, incomplete anthelmintic treatment and reduction of the dose of medication. It is also related to the patient’s own abnormal cellular immune function and may also be caused by the patient’s systemic neurosyphilis.