The experiment of measuring the viscosity coefficient of liquid by the traditional falling ball method is improved:the 3D printing cover is designed by ourselves and combined with electromagnet to realize the small steel ball falling along the central axis of the measuring cylinder;Use the mobile Phone Phyphox App to adjust the device level;Use PASCO Capstone video analysis software to track the position of the ball in real time;Matlab is used to analyze the results and uncertainty．Compared with the traditional manual visual method，the experimental accuracy and efficiency of the improved method are improved．In addition，the effects of ball diameter，inner diameter of measuring cylinder were also studied．