This paper investigates the braking force characteristic of permanent magnet eddy current brake with high acceleration. Compared with the braking force characteristics under quasi-static condition, the braking force considering the effect of high acceleration lags behind the quasi-static braking force before and after the critical speed. Meanwhile, there is a transition phase near the critical speed, and the peak value of the braking force is higher than that in the quasi-static approximation. The calculation of braking force under quasi-static condition is derived by solving the boundary value problem. The accuracy of the analytical model and the finite element model is verified through comparing the results of both models. The influence factors on the braking force characteristics are further analyzed. The results show that the increasing of the conductivity, thickness of conductor plate and the length of the permanent magnets can increase the effect of acceleration. The effect of acceleration has little relation with the permanent magnet height and the air gap length.