Abstract: OBJECTIVE To establish a method to test leak of freeze-dry powder injector container closure system by vacuum degree measurement. METHODS To test the leak of freeze-dry powder injector container closure system by vacuum degree measurement, and compare this method with dye penetrating and decompressing methods. RESULTS It is more sensitive to test leak of freeze-dry powder injector container closure system by vacuum degree measurement both qualitatively and quantitatively, compared with dye penetrating and decompressing methods. CONCLUSION This method is quick, sensitive, simple and effective, and provides preference basis to test leak of freeze-dry powder injector container closure system.