This work considers a new method for establishing the relationship between concentration dependences of self-diffusion coefficients of binary mixture components. The proposed method is based on the concept of self-diffusion coefficient of a system and is similar to the method used to analyze partial values of a system’s extensive properties. From a theoretical point of view, this approach extends the possibilities of self-diffusion analysis and also makes it possible to obtain data on the self-diffusion of the second component based on the concentration dependence of the self-diffusion of one of the components of a binary mixture. The example of its practical application presented in the work is semi-empirical and can be useful when there are limited experimental data. This approach also allows for the first time, based on experimental data, to compare the concentration dependences of the average and partial values of the solution components. This method was tested on 10 binary liquid systems of non-electrolytes with different degrees and character of molecular association.