In this paper,  we build a Bayesian vector auto regression model( BVAR ) and a Markova regime switching vector auto regression model ( MS － BVAR ) .  Through these models,  we study if there are the regime switching effect in Chinese economy and the characteristics of the monetary policy in different regimes based on the core inflation perspective.  The results show that: 1) The regime switching model is more suitable for Chinese economic characteristics,  so Chinese economy presents district system division; 2) There is the large persistence of the core inflation in different regimes,  the average duration of the high inflation regime is 66 months and the average duration of the low inflation regime is 59 months.  The innovation of this paper is that we study the characters of the regime switching of economy and the monetary policy from the core inflation perspective,  estimate the core inflation, exclude the short volatility factor of the inflation and can obviously represent the tre