The invention discloses an elevation angle driving device for a heliostat for tower-type solar thermal power generation. The elevation angle driving device comprises a cylinder body, a sealing mechanism, a telescopic mechanism, a self-locking mechanism, a transmission mechanism and an electric control device. The elevation angle driving device is configured to be used for controlling the elevationangle of a reflecting mirror of the heliostat, and the reflecting mirror is fixed by a frame of the heliostat and rotatably connected to a connecting base. The elevation angle driving device is connected to the connecting base through a pushing rod joint and connected to the frame through a pushing rod adapter. The elevation angle driving device is configured to be used for driving the frame to rotate in the mode of enabling the pushing rod joint to move relative to the pushing rod adapter. According to the heliostat elevation angle driving device, the heliostat can conduct elevation angle adjusting along with sun position changes, and sunlight is reflected to a heat absorption tower more reliably.