Аннотация:Each probabilistic parameter of the Monte Carlo (MC) light transport model has as its analogue a certain physical quantity. This work considers the methodological aspects of construction of the basic MC probabilistic parameters (photon's free pathlength, scattering probability, and scattering angles) based on the corresponding physical quantities. By different examples it is shown that following proper methodology allows for correctly reflecting the features of the particular light transport problem in the MC model.