Abstract: To reveal the squeezing effect on hydro -viscous drive speed regulating start , by using finite element method , the modified transient Reynolds equation , energy equation and temperature -viscosity equation were solved simultaneously to simulate transient behavior of hydro -viscous drive speed regulating start The results showed that with the decrease of oil film thickness , squeezing effect had significant effect on load capacity of oil film during startup process , and the effect varied with oil film thickness During the initial stage of the startup process , squeezing effect had little effect on load capacity of oil film , but the effect became more and more prominent with decreasing of oil film thickness And it was verified by experimental results Key words : hydro -viscous drive speed regulating start , squeezing effect , modified transient Reynolds equation , oil film , load capacity