Abstract: Aiming at the interception of high-speed targets, a new interception guidance law called omnidirectional true proportional navigation (OTPN) was proposed, which adapted to variable-speed interception and can automatically shift interception mode, possessing both head-pursuit and head-on interception capabilities. This guidance law has a wide capture range and can meet the need of omnidirectional interception guidance of high-speed targets. It is found that there are two crack points which meet success conditions in interception guidance of proportional navigation. The signs of navigation ratio for the two crack points are inverse, which leads to the different intercept modes of head-pursuit or head-on interception. In the proposed guidance law, the initial conditions are relaxed through the sign alternating of navigation ratio, and the acceleration limitation was considered as well. The results of numerical simulation verify the validity and effectiveness of OTPN guidance law. Compared with interception simulation of other guidance schemes, under the same intercept conditions, the parameters of capture region, intercept time and control efforts are all superior to those of classical proportional guidance law and retro-proportional guidance law. The major factors influencing interception and capture capabilities of OTPN, such as the maximum acceleration and the value of navigation gain were also studied through capture ability simulation.