Building materials microwave processing demonstrates a great number of perspective advantages as compared to traditional heating methods. In order to upgrade the technology of microwave heating there has been developed a mathematical model of the technological process of microwave energy heat treatment of loose building materials. As a result we have won some calculation correlations, developed a numerical model and calculation algorithms for the analysis and synthesis of the microwave dryer of a loose dielectric with losses while it moves along the working camera. The results of the practical calculations have been carried out with the regard for water load and without it, also with the regard for the changes of the electro- and thermal-physic parameters during the heat treatment as well as disregarding them.