The invention discloses a mobile phone casing toughness detection device with a protective device, which comprises a main casing, a fixing frame, a support column, a support plate and a glass observation window, a hydraulic cylinder is arranged inside the main casing, and the main casing There is an engaging groove on the top surface of the body, the hydraulic cylinder is connected with the hydraulic telescopic rod, and the hydraulic telescopic rod is provided with a scale line, the bottom end of the threaded rod is provided with a fixing piece, and the engaging recess The inside of the groove is provided with a protective cover, the support column is arranged on the top surface of the main housing, and the support column is provided with a calibration plate, the support plate is located at the top of the support column, and the shell body is provided on the support plate, The glass observation window is arranged on the surface of the protective cover. In the mobile phone case toughness testing device with a protective device, the anti-skid pad prevents the case body from sliding during the test, which affects the test results, and the protective cover prevents the fragments of the case body from injuring workers.