Objective To evaluate the cognitive function of Chinese patients with Parkinson's disease PD postsubthalamic nucleus deep brain stimulation (STN-DBS). Methods Cognitive function was assessed by neuropsychological methods in PD patients. Twenty matched healthy persons served as normal controls. t test, analysis of variance, and chi-square analysis were used to compare the difference among the groups. Reliable change index was utilized to analyze the changes in cognition from the individual level. Results (a) Improvement in motor function was significantly better after STN-DBS (P < .01). (b) Notably, the increase error rates of implicit SRTT (serial reaction time task) was significantly higher after STN-DBS as compared with the conservative therapy group (P = .03). (c) The decline of verbal fluency (explicit) was also significantly higher after STN-DBS than that in the medication therapy group (P = .03). (d) In the explicit clock-drawing test, scores had significantly improved after STN-DBS (P = .04). Conclusions STN-DBS as a neuromodulatory tool in the Chinese PD population not only improves motor symptoms but also cognitive function to a certain extent, such as the decline of executive function and verbal fluency. The explicit cognitive decline was significantly quicker than that in patients on medication therapy. The improvement of visiospatial function was also noted. Implicit memory impairment during the 1-year follow-up period was not observed.