By using method of Jones matrix, we analyze all-fiber isolator with polarization maintaining (PM) for optic transmission properties in this paper, the calculated formulas for insertion loss (IL) and backward isolation (IS) can be obtained. The curves of variation of IL IS with relative angle of deviation between nonreciprocal Faraday rotator and non-magnetic rotator as well as PM fiber axes non-aim are given. The results are shown: under ideal condition when optical fiber are non-loss and aiming, IL and IS take (Omega) + and (Omega) - as symmetrical axes, this moment, IL value is minimum, but IS value is maximum. While those angle error in PM fiber is increase, IL data become large, yet IS data change small. If (Omega) + or (Delta) (theta) are 0.573 degree(s), 0.181 degree(s) and 0.057 degree(s) angle off, IS values have a size of 40dB, 50dB and 50dB, respectively. Big or small to angle error with fiber axes will lead to IL~(Omega) -, IS~(Omega) + graphs towards horizontal left of right to displacement, moreover, add or reducing to fiber attenuation will bring about IL~(Omega) -, IS~(Omega) + plots along vertical up or down to shift.