AIM:To investigate the effect of cyclopentolate hydrochloride on cycloplegia in children.METHODS:Sixty children (120 eyes) with refractive error ,aged from 6 to 12,were divided randomly into 3 groups:A,cyclopentolate hydrochloride eyedrop group;B,compound tropicamide group;C,10g/L atropine group. Before and after administration of these eyedrops,pupil size and objective refraction were checked on auto refractor,subjective refraction was checked in phoropter,and phoropter was used to check the accommodation response and residual accommodation respectively by "push-up"method. RESULTS:The time of maximum cycloplegia of cyclo-pentolate hydrochloride was 60 minutes. Under the ma-ximun cycloplegia,the residual accommodation in cyclopentolate hydrochloride eyedrop group and 10g/L atropine group had no significant difference. The residual accommodation in compound tropicamide eyedrop group was stronger than that of the other two goups (P<0.05).CONCLUSION:Cyclopentolate hydrochloride eyedrop is as effective as atropine for the measurement of refractive error in most healthy nonstrabismic children aged from 6 to 12.