[Abstract] Objective To investigate the influence of different setting of respiratory parameters during operation on the postoperative cognitive function after laparoscopic radical prostatectomy. Methods 100 patients undergoing laparoscopic radical prostatectomy were grouped randomly into groupsA, B, C, D and E. All patients were ventilated with identical minute volume 100ml/kg through with respective RR of 8, 10, 12, 14 and 16 times/min respectively. Patients in five groups were all graded by the MMSE at time points of preoperation(T0) , postoperative 1 h(T1), 6 h(T2) , 24 h(T3) , 48 h(T4) ,72 h(T5) , 7 days(T6). S100-β protein were detected at time points of T0, T1, T2, T3. PaCO2 of arterial blood gas were tested before pneumoperitoneum(Ta) and immediately after pneumoperitoneum(Tb). Results PaCO2 at Tb was higher in each group than that at Ta(P<0. 05) . Patients in group D showed the lowest PaCO2 at Tb. The MMSE scores in group D were significantly higher than those in other groups at T1~T3 (P<0. 05) . The values at T1-T3 in groups A, B, C and E were lower than that at T0 (P<0. 05) . And the values at T1 and T2 in group D were lower than that at T0 (P<0. 05). The serum S100-β protein concentrations in each group at T1~T3 were significantly higher than that at T0 (P<0. 05). The serum S100-β protein concentrations in groups A, B, C and E were significantly high than that in group D at T2 and T3 (P<0. 05).Conclusion Early postoperative cognitive function can be improved by regulating intraoperative respiratory parameters properly during laparoscopic radical prostatectomy. Minute ventilation of 100ml/kg combined with RR of 14 times/min may be the reasonable respiratory parameter.