The current theory of military spending allocation is the product of traditional security concept. With the development of national security concept, theoretical innovation is in request. On the basis of the Smith`s neo-classical model and according to the multi-threats environment we established an efficient allocation of military spending model. This model indicates that in the current and future periods, the optimal scale of military spending allocated on protecting non-traditional security should be 4% of total military spending. This conclusion also shows that the ability of carrying out traditional military operation is still the core military capability.