Abstract： Objective To compare the prevalence of neurosyphilis in untreated patients with latent syphilis (LS) versus serofast patients treated for LS in Guangzhou City. Methods A cross-sectional study was performed. Cerebrospinal fluid was obtained from 356 patients who were first diagnosed with LS, and venereal disease research laboratory (VDRL) test was conducted to screen neurosyphilis. Results Among 273 untreated patients with LS, 60 (21.98%) were diagnosed with neurosyphilis, and of the 60 patients, 30 were asymptomatic , and the other 30 were symptomatic. In 83 serofast patients treated for LS, only 1 ( 1.2% ) was diagnosed with neurosyphilis, while no symptom was observed in this patient. In untreated cases of LS, the mean age was significantly lower in patients without neurosyphilis than in those with neurosyphilis.Conclusions Patients with untreated LS are more likely to develop neurosyphilis compared with serofast patients treated for LS, and neurosyphilis mainly occurs in untreated patients with LS, suggesting that untreated latent syphilis is an important risk factor for the development of neurosyphilis.