本文给出的有理分式反Z变换方法可以同时给出因果和逆因果两种序列.由于它避免了现有三种反Z变换方法所必需的确定分式极点的困难及误差,所以使用起来较为方便和精确.它可用来研究子波信号的延迟性质与系统(如滤波器)稳定性和可逆性,还可用来求解线性系统的差分方程,确定分式零点与极点的定位范围. The rational fractional Z-transform method presented in this paper can give both causality and inverse causality at the same time.As it avoids the difficulty and error of determining the fractional pole necessary by the three existing methods of inverse Z transform, Convenient and accurate.It can be used to study the delay property of the wavelet signal and the stability and reversibility of the system (such as the filter), and can also be used to solve the differential equation of the linear system and determine the positioning range of the fractional zero and the pole.