The invention provides a microwave radiometer fully polarimetric digital correlation implementation method comprising the steps that (1) the radio frequency signals of a V channel and an H channel are respectively received from an antenna, the two paths of radio frequency signals are down-converted into intermediate frequency signals and then two power dividing is performed on the intermediate frequency signals of the two channels, and orthogonal transformation is performed on one path of signal after power dividing so that four paths of signals of VI, VQ, HI and HQ are obtained; (2) band-pass sampling is performed on the four paths of intermediate frequency signals of VI, VQ, HI and HQ; (3) digital correlation operation is performed on every two of the data after channel sampling, and then all the correlation results are accumulated within a certain period of integral time; and (4) the four components Tv, Th, T3 and T4 of TB are obtained by using the accumulation result, including all the normal situations of all the channels and the fault situation of a single channel. According to the method, cross-correlation operation is performed on any two inputted signals through a redundant mode so that the reliability of the system can be enhanced.