Data are presented for calculating the main characteristics of a hybrid turbomolecular vacuum pump operating in the molecular gas flow mode. The pump contains a block of turbomolecular stages, an intermediate stage and a molecular stage with screw channels made on a cylindrical rotor. To determine the probabilities of gas molecules passing through the entire flow part of the pump in the forward and reverse directions, the Monte Carlo method in a three-dimensional formulation was used. The program allows you to evaluate the influence of the dynamic and geometric parameters of the flow path on the main characteristics of the pump in order to optimize them.