Abstract: Turbomolecular pumps are widely used in large scale scientific facilities, nuclear physics industry, semiconductors and thin film industry. The radial turbomolecular pump rotor blade array structure is simple, the exhaust end of the blade array is arc-shaped, which is conducive to the forward transmission of gas particles between blades and improves the pumping efficiency. Based on the rarefied gas transport theory and the mathematical particle tracing method, nine different blade structures are compared and analyzed in this paper. COMSOL software is used to simulate the forward and backward transmission probabilities of gas particles between blade rows under different blade structures, and the influence of blade shapes on the forward and backward transmission probabilities of gas particles is explored. The results show that the compression ratio of the turbomolecular pump is increased by one order of magnitude when one side of the rotor blade is convex and the other side is plane. This study has certain reference values and guidance for the design and optimization of turbomolecular pumps.