The invention belongs to the field of photovoltaic technology and discloses a system and method for automatically detecting the curved surface of a solar concentrator. The system includes a transmitting unit, a receiving unit, a guide rail and a computer. The transmitting unit is connected with the guide rail. One end of the guide rail is fixed to the receiving unit. The computer controls the receiving unit to rotate about the central axis of a detected solar concentrator, and controls the transmitting unit to move along the guide rail. The method comprises that the computer controls the transmitting unit and the guide rail to rotate with the receiving unit around the central axis of the detected solar concentrator, the transmitting unit obtains first and second non-diffraction light beamsthat are emitted to the receiving unit to form non-diffraction light moire fringes; the curved surface flatness of a measured point is obtained; the transmitting unit is controlled to move along theguide rail; the above steps are repeated until the entire solar concentrator curved surface flatness is obtained. The system and method solve a problem in the prior art that the detection efficiency and accuracy of the curved surface of the solar concentrator is low, and achieve a technical effect of effectively, accurately and automatically detecting the curved surface of the solar concentrator.