A weapon mount tactical light trigger includes a mount for Picatinny rail to clamp to a shotgun or rifle, a light mount to clamp a tactical light, and a principle mount to joint both mounts with a trigger base fixed at the back. Components of the trigger base include a trigger to switch on/off the tactical light, a circular shaft to allocate the trigger on the trigger base and a fixing bolt to keep the trigger and switch of the light to stay connected under normal conditions. When a user presses the trigger with a finger, the trigger pivots on the circular shaft and exerts pressure to the switch of the tactical light. The structure design of the trigger base is according to the principle of leverage; via pressing the trigger, it exerts pressure to the switch to turn on/off the light; as the mechanism design of this creation avoids possible shortfall of wire conduction and enhance the performance stability of the tactical light.