Objective To analyze the correlation of the bladder spasm after prostate surgery and the density of M2 and M3 muscarinic receptors in bladder mucosa. Methods Patients with benign prostatic hyperplasia (BPH) in our hospital from May 2012 to May 2015 were enrolled as research objects and divided into observation group [BPH with overactive bladder (OAB)] and control group (BPH without OAB). And then the observation group was further divided into bladder spasm subgroup and non-spasm subgroup. The density of M2 and M3 receptors were determined and their correlations with bladder spasm were analyzed. Results The rate of bladder spasm of the observation group was higher than that of the control group. The density of M2 and M3 muscarinic receptors of the observation group was lower than that of the control group. The density of M3 muscarinic receptor in the bladder spasm subgroup was lower than that in the non-spasm subgroup. Conclusions There is a correlation between bladder spasm after prostate surgery and density of M3 muscarinic receptor in bladder mucosa, suggesting M3 receptor may be involved in the pathogenesis of bladder spasm and it can be used as a target to design drugs for prevention and control of bladder spasm.