The principle of 980/1550 fused biconical taper(FBT) polarization maintain fiber(PMF) wavelength division multiplexer(WDM) is analyzed with coupling mode theory;and the method the device is presented.The length and structure of coupling region are effectively controlled by controlling the temperature and size of flame and stretching speed,so the high performance 980/1550 PMF WDM is successfully manufactured with a 1 550 nm PMF and a H11060 single mode fiber(SMF).The measurement results show that the WDM has insert loss of less than 0.2 dB,isolation of 32 dB and polarization maintain characteristic of 22.8 dB at 1 550 nm;and it has insert loss of 0.2 dB and isolation of 14.8 dB at 980 nm.The PMF WDM has the characteristic of polarization maintain at 1 550 nm compared with SMF WDM,and it will accelerate the development of the PMF laser and amplifier.