With the increasing uncertainty of global economic operation, macroprudential and government guarantee have gradually become important means to maintain financial stability. Therefore, a financial accelerator model containing uncertain risk shocks, government guarantees and macro-prudential is constructed to explore the optimal macro-prudential policies under risk shocks and the policy relationship between government guarantees and macro-prudential policies. The findings are as follows: First, macro-prudential monetary policy should simultaneously target multiple signal sources such as capital price and financing premium, while macro-prudential regulatory policy should target a single signal source of capital price. Second, both macro-prudential monetary policy and macro-prudential regulatory policy can weaken the risk impact, among which macro-prudential regulatory policy can directly affect the credit behavior of enterprises and financial intermediaries, with better regulation effect. The other two mix and match although will produce "superposition effect", but the economic boost effect is very limited. Third, while maintaining financial stability, government guarantee will also bring adverse consequences of resource mismatch and crowding out effect. Taking into account monetary policy and macro-prudential supervision can effectively weaken the negative effects of government guarantee. Finally, the choice of monetary policy tools does not significantly affect the effect of macro-prudential policies. The paper conforms to the policy guideline of monetary policy and macro-prudential "two-pillar" regulation framework, and has certain reference significance for improving the financial supervision system and guarding the bottom line of financial risks.