Objective: To study the impairments of cognitive function in first-episode schizophrenia and the potential effectiveness of risperidone and olanzapine monotherapy on first-episode schizophrenia. Methods: A total of 57 first-episode schizophrenia and 30 healthy controls were assessed at baseline, and patients were assessed again after 8-week antipsychotics therapy. Results: The positive and negative symptom scale (PANSS) reductive ratio between the two groups was similar. At baseline, the performance of schizophrenia patients was significant poor than healthy controls in the four domains of cognitive function (P<0.05); after 8-week's antipsychotics therapy, the performance of Trail Making Test (t=3.862, P<0.05) and Verbal Learning (t=-3.073, P<0.05) got significant improvements in patients with risperidone, while in group of patients with olanzapine, the performance of Trail Making Test (t=3.587, P<0.05) and working memory domain (t=-2.891, P<0.05) got significant improvements. Spearman correlation analyses suggested that dosage of risperidone was negatively correlated with the score-reducing rate of the performance of Trail Making Test of patients (r=-0.391, P=0.048). Conclusions: The effects of the two psychotroptic drugs on clinical symptoms and cognitive functions are almost equal. Comprehensive cognitive impairment is found in first-episode schizophrenia, and risperidone and olanzapine could partially improve the performance of cognitive function as well as clinical symptoms. The higher the dosage of risperidone is, the less improvement the patients has in the speed of process domain.