By using mathematical reasoning, this paper demonstrates the economic intervening principle: “Virtual disease is to fill his mother but real disease is to rush down his son” and “ Strong inhibition of the same time, support the weak” based on “Yin Yang Wu Xing” Theory in Traditional Chinese Economics (TCE). We defined generalized relations and generalized reasoning, introduced the concept of steady multilateral systems with two non-compatibility relations, and discussed its energy properties. Later based on the intervening principle of TCE and treated the economic society as a steady multilateral system, it has been proved that the intervening principle above is true. The kernel of this paper is the existence and reasoning of the non-compatibility relations in steady multilateral systems, and it accords with the oriental thinking model.