Abstract: Objective To evaluate the patency of the hand collateral arteries and to compare modified Allen's test (MAT) with thumb perfusion index (PI) test before radial artery puncture. Methods Patients scheduled to undergo selective major surgery were prospectively examined with MAT and thumb PI test before radial artery puncture.Two tests'Results were either positive or negative.Results of both tests were compared in 1 108 patients. Results Among 1 108 patients,two tests both negative was in 1 033 cases;two tests both positive was in 16 cases;the MAT positive,thumb PI test negative was in 57 cases;the MAT negative,thumb PI test positive was in 2 cases,with Chi-square test (χ²=51.27,P<0.05).It meant that there was statistical differences used to evaluate the patency of the hand collateral arteries.The influencing factors were analysed by stepwise logistic regression analyses found that positive rate is related to age and gender by using both Methods (P<0.05). Conclusion The result of thumb PI test show more sensitive than MAT.When applied to radial approach screening,1.62% of patients were not suitable candidates for radial artery puncture.Furthermore,thumb PI test is simpler and convenient compared with MAT in the evaluation of hand collateral arteries,which can replace MAT in clinical application.