The present invention relates to solid detector device for radiation imaging system. The modular solid detector structure includes casing, base board and solid detector array comprising several solid detectors. Inside the casing, there are base board, solid detector array and rack to fix the circuit board; and on the casing, there are sockets in its front side, upper cover and lower cover. The structure features the collimator for collimation and resisting scattering in front of the solid detector array. Compared with available technology, the present invention has greatly reduced scattering, raised scattering resistance of the detector module and raised image definition, and is especially suitable for application in high energy X-ray and no-back collimator radiation imaging check system.