A reciprocating linear pushrod includes a base, a transmission mechanism and a moving mechanism. The transmission mechanism includes a motor and a rotary shaft, and the rotary shaft has a threaded portion including a left-handed thread groove and a right-handed thread groove crossed with each other, and both ends of the left-handed thread groove are communicated to both ends of the right-handed thread groove respectively. The moving mechanism includes a moving rod and a crescent member, and the moving rod has an axial hole and a radial hole and is sheathed on the rotary shaft by the axial hole, and the crescent member is accommodated in the radial hole and embedded into the threaded portion, so that the moving mechanism can be moved reciprocally according to the rotation of the rotary shaft, and this disclosure has the effects of reducing the total volume and simplifying the structure significantly.