The utility model discloses a dry -type transformer winding material detection device based on ray, including gamma ray source (1), detector (2), control module (3) and output module (4), the ray window of gamma ray source (1) arranges and arranges in the winding opposite side of dry -type transformer (5) detected in winding one side, detector (2) of dry -type transformer (5) detected that output and control module (3) of detector (2) link to each other that output and output module (4) of control module (3) link to each other. The utility model has the advantages of need not to disassemble dry -type transformer, simply easy -to -use, do not receive place and equipment constraints, detection fast.