The invention provides a direct correlation-type complete polarization microwave radiometer receiver scaling method. According to a step scaling method, scaling a receiver is completed. The method comprises the following steps: employing signals generated by correlated noise sources of different output temperatures (high temperature source, low temperature source) to fill into a V (vertical polarization) receiver and a H (horizontal polarization) receiver in order through a noise power division network, through four-point scaling, obtaining receiver voltage bias; by utilizing input high temperature source and low temperature source results, obtaining a value of a receiver strip elimination function at a zero point, obtaining reception noise temperatures of the V receiver and the H receiver, and completing normalization processing; through non-relevant noise filling, completing correction of a reception channel residual error, obtaining a multiple association function after final correction, thus obtaining a complete brightness temperature. The method has the characteristics of high scaling precision, simple realization and high reliability, is suitable to spaceborne application, and has wide market application prospect.