Aiming at detecting bearing fault information, which is easily to be submerged in heavy noise and whose characteristics is nonlinear and non-stationary, a method of fault diagnosis based on empirical mode decomposition (EMD) and Duffing oscillator was put forward. This method decomposed the original signals using EMD to find intrinsic mode function (IMF) of containing the fault information, then the dividing value of force making the Duffing oscillator phase orbit changed was got, the inner motivation force frequency was set to the same frequency as the bearing fault, at last the fault was determined according to the change of Duffing oscillator’s phase orbit. The results of experiments show that this method can detect the fault of bearing successfully. 