Objective To reduce infection risks and achieve best protective effect via selection of suitable masks for medical staff through qualitative fit test of 3M FT-30 medical protective mask. Methods From April 1 to 22, 2022, 567 medical staff engaged in medical technology, nursing and logistics work in a hospital were selected for qualitative fit test of medical protective masks organized by department of healthcare-associated infection. 3M FT-30 fit test equipment and qualitative method were applied to test subjects' fit level in wearing medical protective masks. Results All 567 medical staff in the hospital were sensitive to bitter, sensitivity rate was 100%. 567 medical staff underwent fit test with medical protective masks (folding type) produced by Winner Medical Company, out of which 28 failed(failure rate 4.94%). Staff with thin/fat faces or prominent facial features could not wear masks closely, thus were prone to air leakage and failure in test. After changing masks of two other brands, staff failed in the first test were tested again. 11 of them passed with medical protective masks (head-mounted) from Zhende Medical Supplies Co., Ltd. 16 medical staff with thin face, pointed chin and collapsed nose passed the test with Siwo D920 medical protective mask. 1 medical staff failed with medical protective masks from all three brands. There were statistical differences in test failure rates when subjects wore medical protective masks of the same type and batch for different movements during test (all P < 0.05). Conclusion Qualitative fit test for masks can help medical staff select suitable medical protective masks based on test results, improve their protection awareness and reduce infection risks.