With conducting of studies of the processes of the dissolution of crystalline substances the complexities with the determination of the stage of the process of dissolution appear. For these purposes usually are used either the instruments measuring the density solution or the weights, which make it possible to determine a quantity of still undisclosed substance. But both methods have deficiencies (difficulties of measurement with small quantities of substance, high price and not the universality of measuring equipment). The application of a method of acoustic emission (AE) makes it possible to conduct a study of the processes of dissolution without depending on the volumes of substances and does not require creation for this of special condition. In the present time it is considered that graph summary AE (Nae) in the process of the dissolution of crystals bears monotonic nature. It is assumed that an equal quantity of solvent causes equal increase In Nae. Thus at each subsequent moment of time the value of Nae must be lowered proportionally to the decrease of the share of undisclosed the substance. The checking of this assertion it was carried out for the crystals of salt and sugar, which are the typical representatives of electrolytes and nonelectrolytes. In this case for the sugar the experiment was conducted with the different values of initial temperature, which increased the reaction rate of dissolution in 10 times. In the course of experiment it was revealed, that the nature of graph is differed from that assumed the presence of the additional of the splash of Ńae in the process of dissolution. In this case the nature of the flow process it does not depend on the temperature.