Objective To investigate the effect of nicardipine on perioperative insulin sensitivity in patients with essential hypertension(EH). Methods Thirty-eight patients undergoing lobectomy continuously after induction of anesthesia in group N, while normal saline was infused in group C instead of nicardipine. Blood samples were taken immediately before induction of anesthesia(T_0), 2 h after skin incision(T_1) ,4 h after surgery(T_2) and 24 h after surgery(T_3). Blood glucose(BG) and plasma insulin (Ins) were measured. The Insulin sensitivity index (ISI) was calculated. Results Values of BG at T_2and T_3 in group C were higher than those at T_0 (P<0. 05). Value of Ins at T_2 in group C was higher than that at T_0 (P<0. 05),which at T_3 in group C was significantly higher than that at T_0 (P<0. 01). ISI at T_2 in group C was lower than that at T_0 (P<0. 05) ,which at T_3 in group C was lower significantly than that at T_0 (P<0. 01). Values of BG and Ins at T_3 in group N were higher than those at T_0 (P<0. 05), ISI at T_3 in group N was lower than that at T_0 (P<0. 05). Value of BG at T_2 was significantly lower in group N than that in group C(P<0. 05). Value of Ins at T_3 was significantly lower in group N than that in group C(P<0. 01). ISI at T_2 and T_3 in group N was min~(-1) infused continuously during and after lobectomy can increase significantly insulin sensitivity and improve postopertive insulin resistance state in EH patients.