Objective To analyze the reason why ALT had high failure rate after blood donor screening. Methods Ran-domly selected 10647 blood donors as control group and 12129 blood donors as the screening group, statistics for the failure rate of ALT, HBsAg, anti-HCV, anti-HIV and anti-TP. In the screening group, visually inspect ALT unquali-fied specimens and review on dry type biochemistry analyzer. Analyzed the consistencies between the street screening results and laboratory test results. Results The ALT, anti HCV positive rate and total unqualified rate of screening group decreased more significantly than that of the control group, but the HBsAg, anti TP positive rate decreased in-conspicuously. Most of the reasons for ALT unqualified in the screening group was chyle blood abnormalities. Screening for ALT on street dry type biochemistry analyzer had some missing. Conclusion In order to improve the qualified rate of blood, chyle blood screening is necessary before blood donor screening, moreover, we should strengthen the quality control of street screening.