Abstract: A database method to get nonlinear oil film force of the finite width hydrodynamic journal bearings is presented. Thus some state variables are transformed from infinite to finite by using Poincare transformation and a nonlinear oil film force database of hydrodynamic bearings is established in the transformed phase space by solving Reynolds equation. The nonlinear oil film force with respect to state variables can be obtained from the database in a shorted time. The accuracy of the database is testified using time transient analysis of practical journal bearing and Poincare mapping method.