The invention discloses an unknown environment mapping method for a single-beam laser of aircraft, which belongs to the field of three-dimensional map reconstruction technology. Firstly, the data collected by a single-beam LiDAR is aligned with the timestamp of the stepper motor, and the obtained point cloud data is filtered and matched to obtain three-dimensional map information. The pose of the aircraft is estimated by the wheel odometer and IMU, and the loop detection is performed to reduce the cumulative error and update the three-dimensional map information in real time. The frontier search algorithm is used to determine the target point of the aircraft flight, the A* algorithm is used to plan the path trajectory, and the B-spline curve optimization algorithm is used to make the trajectory of the aircraft smoother. The control command is sent to the aircraft, and then the global three-dimensional map of the unknown environment is obtained.