Objective To study, discuss and analyze the reasons for deviations in drug test results and find out methods for quality control. Methods 150 drug samples from October 2022 to October 2023 were randomly collected and tested using two methods: UV spectrophotometry and high performance liquid chromatography. The results of the drug samples tested by the two methods were comparatively analyzed. Find out the reasons for deviations in drug test results, and finally conduct further research based on the situation of the drugs to find ways to control drug quality. Results The deviation rate of the drug detected by UV spectrophotometry was 4%, and the deviation rate of the test results obtained by high-performance liquid chromatography was 3.33%. The difference between the groups was not statistically significant (P>0.05). The two methods were used to detect the deviation rate. The deviation rate of drug test results is different, but the difference is not significant. Conclusion There are many factors that cause deviations in drug testing results. To ensure that drug testing results have high accuracy, scientific and reasonable testing methods and technologies must be used to ensure the standardization of operations during testing and reduce the impact of variable factors on The influence of test results can reduce errors, improve the accuracy of test results, maximize the efficacy of drugs, and ensure the quality of drugs.