Abstract: Diffractive grating element based on yttrium aluminum garnet (YAG) transparent ceramics substrate was fabricated and researched. A uniform dense metal chrome film was deposited on YAG transparent ceramics by direct current(DC) reactive magnetron sputtering. The YAG transparent ceramics with hard mask were obtained. The photolithography was accomplished by contact UV-lithography system, and the YAG transparent ceramics sample with diffractive grating was obtained by trial and error. Testing results show the thickness of chrome film is 0.072 m by optical profiler, the details of diffractive grating in the sample are remained perfectly. The feasibility of fabricating diffractive grating by substituting YAG transparent ceramics for traditional photolithography substrate has also been proved by the diffraction pattern of this grating. It is concluded that this research makes possible to use diffractive grating in a more complex environment and has broad prospects in application.