In order to overcome the complicated structure and high prices of the hydraulic retarder and the serious thermal recession problem of braking torque of the conventional eddy current brake, a self excited and liquid cooled eddy current retarder (SL-ECR) structure was proposed. The model of braking system and generating system of the SL-ECR was established and the magnetic circuit structure was analyzed. The electromagnetic field model, the braking performance and thermal field of the SL-ECR were analyzed by using finite element method. A 2000N·m SL-ECR was produced and tested. The braking performance and the generator performance were tested. The results show that the difference between the finite element analysis results and the experiment results was 6%. The temperature of the water wipe was 85℃ when the braking power was 180kW. The braking torque decreased by 10.4% in the continuous braking stage. The braking torque could reach 2000N·m when the speed was 1500r/min and the coil current was 30A, while the excitation power was only 720W by the vehicle.