Objective To investigate the effect of 12 Fr catheter on the catheteration for the patients with prostatic hypertrophy after stroke. Methods One hundred and four sixteen patients with prostatic hypertrophy from urinary detention were divided into the control group (n=80) and the observation group (n=84) based on the odd and even numbers of admission date according to a digit random table. The control group received catheteration with a 14~20 Fr catheter, and the observation group did with a 12 Fr catheter. The two groups were compared in terms of pains, urethral injury and leakage of urine during intubation. Result The pain, urethral injury, leakage of urine in the observation group were all significantly lowered than those of the control group (all P<0.05). Conclusions 12 Fr catheter for catheteration for the patients with post-stroke prostatic hypertrophy can significantly reduce the degree of pain, the urethral injury and leakage of urine. Thus it is worthy of clinical application.