Abstract: This article makes a multiple threshold test on the monetary authorities’ monetary policy rules under different stages of business cycle, finding that the nominal interest rate adjustments of the monetary authorities have an obvious asymmetric preference. During the booms, the monetary authorities’ nominal interest rate adjustments have a preference for avoiding inflation, and their operations will be inclined to output gap under an austerity．Later on, for further study on the dynamic adjustment process of monetary policy rules in different stages, this article employs a LT-TVP-VAR model to estimate a time-varying parameter monetary policy rule under the New Keynesian framework again. The results show that the monetary policy rule has a gradient feature with business cycle changes, which is difficult to detect. Therefore, this kind of slight change has no passive impacts on public expectations and the monetary authorities’reputation, which guarantees the monetary authorities make effective reaction to the change of economic condition without losing their credibility. 

Keywords: Business Cycle, Ruled Monetary Policy, Multiple Threshold Model, LT-TVP-VAR.