【Abstract】 Objective: To evaluate the platelet (PLT) count performance quality of Sysmex XE-5000 automatic hematology analyzer. Methods: PLT was counted by Sysmex XE-5000 automatic hematology analyzer with electric impedance (PLT-I) and optical (PLT-O) methods to test the precision, linear range and interference. The count results of PLT-I and PLT-O were compared with those of microscopic count method (PLT-M) respectively. All data were analyzed by SPSS 12.0. Results：The within-batch precisions of PLT-I and PLT-O were 1.30% and 1.40% and the between-batch precisions were 1.87% and 2.39%. The ranges of carry-over ratio are from 0 to 1.32% with PLT-I and from 0 to 1.17% with PLT-O,the average carry-over ratio of PLT-I and PLT-O were 0.44% and 0.33%. The correlation coeffients (r)were 0.991, 0.997, 0.997 with PLT-I and 0.997, 0.998, 0.992 with PLT-O in lower,medium and high value specimens. The result showed that the PLT-O method had great ability of anti-interference in RBC fragment interference experiment (t=1.14,p>0.05).There were significant correlations in the results between PLT-I and PLT-M and between PLT-O and PLT-M. Conclusion: Sysmex XE- 5000 automatic hematology analyzer is of high accuracy, good repeatability, quickness and anti- interference for platelet count. it is satisfied with needs of blood platelet count in the clinical laboratory.