The invention discloses a heat dissipation device for a controller of an electric vehicle whihci comprises a bottom plate and a baffle, A baffle includes a left baffle and a right baffle, A left baffle plate is provide with a slider 1, At both end of that left baffle plate, a cooling water pipe 1 and a fixing block adjust bolt 1 are arranged, At a threaded joint of that fix block adjusting bolt and the left baffle plate, a fixing block slide groove is arranged, A fixing block 1 is slidably connected with the fixing block 1 on the fixing block slide groove 1, A slide block 2 is arranged on theright baffle plate, At one end of that right baffle plate, a fixing block adjust bolt 2 is threadably connected, A cool water pipe 2 is arranged below the fixing block adjusting bolt 2, a fixing blocksliding groove 2 is arranged at the threaded connection between the fixing block adjusting bolt 2 and the right baffle plate, the fixing block 2 is slidably connected with the fixing block 2, a fan is arranged at the middle position of the bottom plate, support plates are arranged at the left and right sides of the bottom plate, and the support plate is threaded with the adjusting bolt. Comparedwith the prior art, the invention has the advantages of simple structure, convenient installation, adaptability to various controller sizes, and good heat dissipation effect.