Abstract: In order to improve the proficiency level of the laboratories for plastics flexural property testing, Shandong nonmetallic materials institute firstly organized "test for plastics flexural property" proficiency testing program. The statistical results of the proficiency testing for plastics flexural property were analyzed respectively by classic statistical method, iteration robust method and quartile robust method. Also, the overall level of the plastics flexural property was evaluated and the possible causes of deviation were pointed out. The results show that in the data statistics of laboratory proficiency testing, the robust statistical method was the best to avoid the influence of extreme data. Test results for plastics flexural property of about 12% laboratories had problems and the results deviation may be related to the equipment, the environment and the personnel.