Abstract: Based on geometric optics method,the atmospheric profiles are inverted from the excess phase delays of a COSMIC RO event(ROE) occurring on June 6,2007 over Australia.The inverted profiles,including bending angle profile,refractivity profile,dry temperature profile and humidity profile, are compared with corresponding data products provided by COSMIC data analysis and archive center(CDAAC).The results show that the application of radio holographic method to the inversion process of CDAAC leads to the differences between the profiles inverted by this paper and by CDAAC in the lower troposphere(LT). With a radiosonde sounding occuring within 2 hours and 300 km of the ROE as reference,errors are found in the refractivity profiles inverted by this paper and by CDAAC in LT.For the chosen ROE,the errors in the humidity profile provided by CDAAC,which is inverted with variational method,are even larger than the humidity profile inverted by us with direct method.