For the issues of design preferences,braking force fluctuation of eddy current retarder of heavy duty construction vehicle during use,the heavy duty construction vehicle eddy current retarder is regarded as research object,the calculation formula of retarder braking torque is deduced,and combine with the actual object of key parameters and the influence of each parameters on braking performance are considered,the optimization design of the eddy current retarder is carried out through optimization design theory. Finally,the optimized model is validated through the experiment. The results show that the eddy current retarder of heavy duty construction vehicle after optimization design can improve the fluctuation of braking torque and braking time.