Abstract: A power gas tank cover including a motor, a collar including an annular portion, a tubular portion formed at one side of the annular portion and having a hole communicated with an opening of the annular portion, a recess between the annular portion and the neck portion, and an inclined track on an inner side of the neck portion, a worm shaft inserted into the tubular portion and connected with the motor, a sleeve fitted in the inclined track, an inner jacket being a cone-shaped member with a first orifice, an outer jacket rotatably fitted on the inner jacket and provided at a lower portion with a worm gear meshed with the worm shaft, a pressure relief valve arranged on a top of said inner jacket, and a transmission shaft pivotally connected with the outer jacket at an end and with a gas tank door at another.