The invention relates to the technical field of building lighting, and discloses an environment-friendly mosquito trapping device for building construction site lighting. The environment-friendly mosquito trapping device comprises a top plate, movable rods are movably hinged to the left end and the right end of the top plate, and moving grooves are formed in the movable rods. According to the environment-friendly mosquito trapping device, the movable rods are adjusted, when the movable rods are in a horizontal state, under the action of a first guide rod and a second guide rod, a sealing box is horizontally placed, a connecting rod makes contact with a supporting plate, the sealing box is in a sealed state, then gas enters a rotating wheel under the action of a suction fan, at the moment, suction force exists in a slotted hole, mosquitoes can be adsorbed to the slotted hole, then a sliding rod can slide to the position close to the suction fan due to the fact that the suction force is large at the position, close to the suction fan, of a fixed frame, the caliber of the slotted hole is increased under the action of an arc-shaped bag, and the mosquitoes can be sucked into the sealing box; and then when the fixed frame is far away from the suction fan, the caliber of the slotted hole is decreased to prevent the mosquitoes from flying out, and the trapping effect is achieved.