The invention provides a brake energy absorbing device and a control method thereof. The brake energy absorbing device comprises a disconnecting switch QS1, a main direct current contactor KM1, an electric reactor L and a capacitor C. The disconnecting switch QS1 is in series connection between a direct-current source anode and a direct-current source cathode. The main direct current contactor KM1 is in parallel connection with a series branch composed of a buffer contactor KM2 and a resistor R1. A capacitor C1 is in parallel connection with a chopped wave branch. The chopped wave branch comprises an IGBT module V1 and a fast recovery diode V2 which are in series connection. The fast recovery diode V2 is in parallel connection with a brake resistor R2. The brake energy absorbing device and the control method thereof have the beneficial effects that the effect that the phenomenon of sharp fluctuation of direct-current busbar voltage is avoided is ensured, very good rapidity and certain stability are achieved, and the whole size of the brake energy absorbing device and the production cost are reduced greatly.