  Thermal balance of the jet in the source SS433 is considered with account of
radiative and adiabatic cooling, and different heating mechanisms. We consider
jet heating by the inverse Compton effect of coronal hard X-ray quanta on jet
electrons, the influence of shock wave propagation along the jet, and jet
kinetic energy transformation into heat via Coulomb collisions of jet and
corona protons. The most important heating mechanism for the source SS433 turns
out to be Coulomb collisions of jet particles with the surrounding medium.
