AIM:To investigate the effect of Cyclogyl and compound tropicamide on cycloplegia with objective assessment to guide their clinical work. METHODS: Totally 60 cases(120 eyes) of myopia and hyperopia(each of 50%) aged 12 to 40 years from 2010/12 to 2011/03 were randomly selected.They were conducted mydriasis with domestic compound tropicamide eye drops 4 times, and retinoscopy 45 minutes later, and measured the amount of residual accommodation with integrated refractor.They were reinspected with Cyclogyl on the second day. RESULTS: In the hyperopia group, there were significant differences in refraction results between Cyclogyl and compound tropicamide (P<0.01); there were less differences in the myopia group (P<0.05), but still statistically significant. CONCLUSION:Clinically for refraction of patients with refractive error, compound tropicamide eye drops is an effective cycloplegic, but because of its limited cycloplegia and relaxation of accommodation, especially in hyperopic patients, it should be integrated with other relaxation methods, such as Cyclogyl, to get the final glasses prescription.