The invention discloses a missile body rolling angle detection system and method based on geomagnetism and sunlight angle. The system comprises four photosensitive tubes, a geomagnetic measurement module, a GPS module and a controller, wherein the geomagnetic measurement module, the GPS module and the controller are arranged in a missile body in sequence from top to bottom; the geomagnetic measurement module is located at the top of the bullet of the missile body, and the four photosensitive tubes are uniformly embedded in the outer wall of the missile body in the circumferential direction; and the output end of geomagnetic measurement module, the output end of the GPS module and the output ends of the four photosensitive tubes are connected with the input end of the controller. Accordingto the system and the method, the detection of missile body rolling angles can be realized without using a gyroscope and an accelerometer; and the structure is simple, and the cost is low.