Abstract: This paper constructs a 111-dimensional indicator system of China's external situation, and synthesizes the external economic and financial uncertainty index based on the high-dimensional dynamic factor model and two-step weighting method. On the basis of building a theoretical framework for the relationship between external uncertainty and monetary policy independence, LST⁃VAR and TVP-VAR models are used for reference from the risk aversion, exchange rate stability and capital openness levels respectively, This paper empirically examines the mechanisms of external economic and financial uncertainties on the independence of China's quantitative and price based monetary policies. The research finds that: Firstly, the relative relationship between the external economy and financial uncertainty is closely related to the source of impact. Before 2011, the volatility of the global financial submarket made the external financial uncertainty significantly greater than the external economic uncertainty. After 2011, the uncertainty factors of the global real economy reversed the relationship between the magnitude of the two external uncertainties. Secondly,External uncertainty will enhance global risk aversion. When global risk aversion, exchange rate stability and capital account openness are high, external uncertainty will significantly weaken the independence of quantitative and price- based monetary policy,among which external financial uncertainty has a greater short-term negative impact on the independence of monetary policy. The research of this paper provides beneficial policy enlightenment for preventing external uncertainty shocks, enhancing the independence of monetary policy, and maintaining the overall stability of the economy.