Well known conclusions or the general hydrodynamic theory,heat- and mass transfer are widely used in the description of fluidized processes. The authors critically apply these conclusions to the processes of heat-,mass and momentum exchange in fluidized beds and especially to the correlation of experimental data. Here new principles of analyzing the momentum and heat exchange processes between the gas flow and solid particles in fluidized bed are derived: the "external" problem of hydrodynamics is applied;the behaviour of a solid phase is investigated (peculiarities of polydispersed bed and the motion of particles in the bed; the use of a heat transfer coefficient and the Nusselt number in the investigation of heat exchange between the gas and fluidized bed criticized while the use of dimensioless temperature is suggested; the analysis of the heat treatment process of solid particles is conducted in Lagrange variables.