The study consists of two periods: screening period (2 weeks) and double-blind treatment period (8 weeks). After the screening period, generalized anxiety disorder patients who satisfies the inclusion criteria are randomly assigned in the 1:1:1 ratio to receive either placebo or Toludesvenlafaxine Hydrochloride Sustained-release Tablets at two dose levels (80 ,160 mg/day) for 8 weeks. Participants are evaluated at screening, baseline visits and double-blind period.