The invention discloses a power battery fixing device for electric vehicle. The structure comprises a storage tank, Handle, control button, slider control structure, fixing frame, internal fixing device, The fixing frame is provided with a storage tank, the fixing frame and the storage tank are formed into an integrated structure, the handle is provided with a pair of, arched structure, The handleis embedded at the upper end of the fixing frame, A control button is adjacent to the slider control structure, the slider control structure is connected with an internal fixing device, and the internal fixing device is arranged inside the fixing frame. When the battery is taken out, the ratchet transmission mechanism and the transmission of the inflating structure are driven by the lead screw transmission mechanism to realize the expansion of the air bag, thereby facilitating the take-out of the battery. When the battery is installed, one auxiliary mechanism is used to fix the two sides of the battery, two auxiliary mechanisms are used to fix the upper and lower ends of the battery, and three auxiliary mechanisms are used to fix the middle part of the battery. The whole structure securesthe battery firmly, and the battery can be taken out easily and conveniently.