The invention discloses an environment-friendly unmanned aerial vehicle for constructional engineering. The environment-friendly unmanned aerial vehicle for constructional engineering comprises a vehicle body, a tail wing and vehicle wings and is characterized in that the vehicle wings are connected with the vehicle body through a folding mechanism; an undercarriage is arranged below the vehicle body and comprises an installation seat connected to the position below the vehicle body, a third rotary shaft arranged on the installation seat, a supporting column, a buffer spring, a cross beam, a supporting beam, two supporting legs and two connecting rods; the upper end of the supporting column penetrates the cross beam and is fixedly connected with the third rotary shaft; the lower end of the supporting column is inserted on the supporting beam; the supporting beam can move linearly along the supporting column; the supporting column is sleeved with the buffer spring; and the buffer spring is located between the cross beam and the supporting beam. By the adoption of the environment-friendly unmanned aerial vehicle, due to the fact that the undercarriage is arranged below the vehicle body, a buffering effect can be achieved in the taking-off and landing processes, and the vehicle body is protected against damage.