Uncovered Interest Rate Parity puzzle four hypothesis test Abstract: This paper uses survey data on market exchange rates to carry out an empirical investigation of the RMB against the U.S. dollar uncovered interest parity. It incorporates a nonlinear time-varying coefficient depends on"risk premium", "Transaction costs","foreign exchange market intervention"and"limited arbitrage which are four uncovered interest parity hypothesis. The results show that transaction costs will change the direction of exchange rate spreads reaction; one regime with high transaction cost has persistent deviations from UIP, in the regime with low cost, the UlP hold. Time-varying risk premium has no significant effect on uiP deviation. The central bank's intervention and cross-border arbitrage return will change the RMB response speed to interest rate spreads, cause the UIP deviation coefficient more serious. Recently, RMB UIP deviations are increasingly penetrating, which means that the contradiction between the gradual opening of Chinas unt and the rmb exchange rate formation is increasingly severe Key words: Uncovered interest parity Exchange rate expectation Foreign exchange market intervention Nonlinear adjustment2 Uncovered Interest Rate Parity Puzzle: four hypothesis test Abstract：This paper uses survey data on market exchange rates to carry out an empirical investigation of the RMB against the U.S. dollar uncovered interest parity. It incorporates a nonlinear time-varying coefficient depends on "risk premium", "Transaction costs", "foreign exchange market intervention "and" limited arbitrage ", which are four uncovered interest parity hypothesis. The results show that transaction costs will change the direction of exchange rate spreads reaction: one regime with high transaction cost has persistent deviations from UIP, in the regime with low cost, the UIP hold. Time-varying risk premium has no significant effect on UIP deviation. The central bank's intervention and cross-border arbitrage return will change the RMB response speed to interest rate spreads, cause the UIP deviation coefficient more serious. Recently, RMB UIP deviations are increasingly penetrating, which means that the contradiction between the gradual opening of China's capital account and the RMB exchange rate formation is increasingly severe. Key words：Uncovered interest parity Exchange rate expectation Foreign exchange market intervention Nonlinear adjustment