Abstract: Laboratories participating in proficiency testing of charpy impact strength determination of plastic were assessed. The normal distribution test and Z score statistics were carried out for the test results of laboratories with qualified equipment, and factors could affect the accuracy of test results were summarized. The results show that test samples were uniform and stable. Three laboratories were not included in the statistics due to unqualified equipment, the test results of the other 19 laboratories were satisfactory, which indicated that laboratories participating in the proficiency testing had a good ability to test the charpy impact strength of plastic.