A method using internal samples at reservoirs to carry out weighting and compile a logging crossplot includes the steps of fully considering the difference of quantity of core analysis samples of the reservoirs in oildom target stratums and the difference between logging information resolution ratio and core analysis sampling resolution ratio, and carrying out weighting processing on testing values of all the core analysis samples in the reservoirs. Through the processing, the method fully reflects the difference of thickness of each reservoir and the internal sample quantity, accords with requirements for sample space in statistics, and obviously improves drawing precision of the logging crossplot.