Abstract: The product high-order ambiguity function (PHAF), originally proposed for analyzing multicomponent polynomial phase signal (mc-PPS), is still troubled by interference terms in the estimation of mc-PPS. In this paper, a scheme to mitigate interference terms is proposed by iteratively filtering all the components corresponding to the strongest peak of the PHAF. The improved version of PHAF has better precision, smaller blind area, threshold of signal to noise ratio, can estimate lower order phase coefficients. The performance of the new method is verified by simulations with mc-PPS's.