The utility model discloses a bi-articulated safety pin mechanism for a power catwalk machine transmission rack, which mainly comprises a safety pin, an upper connecting block, a transmission rod, a lower connecting block, a base lifting pin, a tension spring, a pin shaft, an upper cylinder sleeve, a lower cylinder sleeve and the like. When the transmission rack is on the ground, since the base lifting pin under the bi-articulated safety pin mechanism is pressed, the safety pin is collected into the working surface of the transmission rack so as to allow a tubular column to be transversely sent into and sent out of the V-shaped slot of the transmission rack conveniently, and when the transmission rack leaves the ground, the safety pin is popped out under the effect of the spring, so as to play the effect of preventing the tubular column from rolling out of the transmission rack transversely during a transporting process. The bi-articulated safety pin mechanism provided by the invention is mainly used for ensuring transport safety of the tubular column for petroleum drilling, the entire structure of the mechanism is simple and reliable, the manufacturing cost is low, safety and reliability are high, tubular column transportation procedures are simplified, and the safety and the efficiency of tubular column transport are improved.