To tackle with the problem that the rotation of displaying image disturbs the operator in modern weapon aiming system,this article proposes a kind of design for eliminating display rotation of image-watching-aiming-system based on Field Programmable Gate Array(FPGA). This scheme obtains rotation carriage information from the plat roof carriage sensor,rotates the displaying image reversely,eliminates the rotation of displaying image,and conveniences the aiming of operators. This scheme also expands the ability of changeable focus successively,solves the inconsistence of resolution ratio between the displaying and the operational stick,and improves the perfect precision of aiming.