Abstract: The application of detecting SF6 leaking by IR laser imaging system has an important signification. If the emission line of the grating tunable laser is right within the absorb range of SF6, the reflecting line can be received by the IR detector and the system will display the SF6 leaking situation. SF6 gas will absorb more IR spectrum around the center of 10.56μm, so high stability laser output and single output frequency are requested.