To study the characteristics and influencing factors of cognition on patients with Parkinson's disease (PD) in Xi'an in order to provide evidence for early recognition and treatment of cognitive impairment on PD patients. Clinically defined PD patients from 7 hospitals in Xi'an from Jan. to Apr. 2007 were assessed with mini-mental state examination (MMSE) and Montreal cognitive assessment (MOCA) for whole cognitive function. Furthermore, Fuld object memory test (FOM) was used to assess delayed memory while rapid verbal retrieve (RVR) was used to assess language fluency. Digit span subtest was used to assess attention and building blocks was used to assess visual space function respectively. 100 PD patients were recruited, including 52 men and 48 women, from 43 to 86 years old (65.6 +/- 17.1). MMSE scores was used as the standard for Recognition, PD with cognitive impairment accounted for 16%. According to MOCA scores, with PD cognitive disturbances accounted for 83%. Ability for calculation, short-term memory, visual space function, abstract capability, attention and language fluency dysfunction were main cognitive disturbances of PD. Analysis from single factor logistic regression showed that education, age of onset and gender were closely related to the occurrence of cognitive impairment on PD patients. Cognitive impairment was common in PD. Ability of calculation, short-term memory, visual space function, abstract capability, attention and language fluency dysfunction were main cognitive disturbances of PD. Cognitive impairment of PD was more likely to occur with low degree of education, late onset of PD, and being female.