Objective To study the joint angle and contact force of the thumb during one-handed operation on mobile phones, analyze the biomechanical characteristics and influencing factors of the thumb joint angle and contact force, and provide the biomechanical basis for prevention, rehabilitation and treatment of thumb stenosing tenosynovitis. Methods Vicon optical motion capture system and resistive thin film force sensor were used to collect the thumb joint angle and fingertip contact force of college volunteers when they operated mobile phones with one hand, and statistical multi-factor correlation analysis on human body parameters, joint angle and contact force was conducted. Results The joint angle and contact force of one-handed mobile phone operation, such as sliding up, turning clockwise, right pointing, left pointing and sliding left, were obtained through the instrument measurement. Statistical analysis showed that hand length and thumb length had a significant influence on the average angle and the maximum contact force of each joint (P<0. 05), and hand length was basically negatively correlated with the average angle and the maximum contact force of metacarpophalangeal joints. Conclusions Reducing the amplitude of thumb movement to avoid thumb hyperextension or flexion, or reducing the frequency of using mobile phones, or reducing the force of operating mobile phones, can reduce the friction between flexor tendon and tendon sheath of thumb and bone fiber duct, as well as the mutual squeezing force to some extent, thus reducing the formation of thumb stenosing tenosynovitis.