Abstract: In this paper,the PPP method used for ZWD(zenith wet delay) estimation and the method of PW inversion were investigated.And adopting different Tm model's affect to the PW's precision is analysized.The ZWD and PW of some SuomiNet stations are solved using the software TriP designed by Wuhan University.The results were compared with the ZWD and PW result provided by NOAA.For the resolution of the ZWD results solved by TriP are lower than the results provided by NOAA.We get the corresponding results through interpolation.Most RMS of the ZWD difference between the results solved by TriP and the results provided by NOAA are within 8 mm.The RMS of the PW difference are less than 1.3 mm.The analysis demonstrate that a good agreement between the PW results solved by PPP method and PW results provided by NOAA are achieved.