An electromagnetic positioning frame for measuring liquid viscosity coefficient is designed to solve the problems existing in the existing instrument for measuring liquid viscosity coefficient by falling ball method. In this paper, the experimental equipment was improved, through the principle of electromagnet suck balls, effectively reduce the pollution caused by experimental operation experimental liquid experimental liquid pollution and the outside world, and the design of the cone type electromagnet and semicircular canals the whereabouts of precise control of the ball position, the largest possible meet the requirements of the experiment principle of ball falling position, effectively eliminate the traditional instruments existing many problems when doing the experiment, ensure the accurate and metal ball along the center of container, the experiment operating accuracy has improved significantly.