Objective To investigate the sources of cross-contamination in the determination of uric acid with automatic biochemical analyzer. Methods The contamination reagent in the determination of UA were Screened out. After determining the interference reagent, the cross-contamination tests were performed. Results In combination detection, HDL measurement had contamination in the UA measurement. The reagent contamination trial found a significant positive interference of HDL reagent to UA test results. Conclusion Automatic biochemical analyzer has cross-contamination in the determination of uric acid. The cross-contamination could be reduced and avoided by adjusting the project detection order, establishing special cleaning procedures for reagent needle, or by replacing the reagents with anti-contamination ingredients.