A coaxial tilt-rotor unmanned aerial vehicle (CTRUAV) and a control method thereof. The CTRUAV includes three rotor modules, five rotors with motors and a control system. The three rotor modules are in an inverted triangle layout. The left and right coaxial tiltable rotor modules in the front of the CTRUAV can rotate around the plane of a fuselage. A rear rotor is installed on the rear fixed-axis rotor module. Two pairs of coaxial rotors are respectively installed on the left and right coaxial tiltable rotor modules. The left and right coaxial tiltable rotor modules include an upper rotor and a lower rotor respectively; the upper rotor and the lower rotor have opposite rotation directions and the same rotation speed during the flight. In the two pairs of coaxial rotors, the rotors on the same layers have opposite rotation directions, and the rotors on different layers have the same rotation directions.