Abstract: A new experimental method to identify the dynamic coefficients for the oil film in a journal bearing (including the oil film stiffness and damping coefficients) is presented on the base of vibration theory and least square method. The identifying model was established and experimental research undertaken. Experimental results showed that this method can decrease void signals and improve the accuracy of identification. By using this new method, it is not necessary to know some characteristics of the bearing pedestal before hand. And the equivalent mass of the journal can also be identified at the same time.