To investigate the influencing factors of whether a ruler suspended at the edge under paper cover can detach when struck by weight，this paper establishes a mechanical model based on the lever model and suction cup model． The control variable method is employed for experiments，and the ruler ＇ s downward trajectory is tracked using Tracker software.Theoretical validation is conducted through COMSOL software simulation and Matlab software fitting，leading to relatively accurate conclusions from the mechanical model．The experimental and simulation results align with theoretical analysis． The study reveals that the ruler＇s maximum deflection angle，ball mass，ball drop height，ruler extension ratio，paper size，and ruler material are the primary factors affecting ruler detachment．