Abstract: In order to study the influence of overcharge current on thermal runaway, numerical model was adopted to calculate the effects of different currents (1<i<C</i<, 2<i<C</i<, 3<i<C</i< and 4<i<C</i<) on thermal runaway under overcharge conditions. A three-dimensional electrochemical-thermal model based on Multiphysics coupling method was built and critical temperature, critical time and heat distribution of thermal runaway with different currents were calculated. Model feasibility was also verified, the error between simulation and experiment was less than 8%. Overcharge has remarkable effects on the thermal runaway of lithium-ion battery in various ways. Results show that the greater the overcharge current is, the shorter the thermal runaway time will be, the higher the critical temperature will become, and the larger the temperature differences between different parts of and the surface and the interior of the battery will be.