Abstract: In order to study the effects of ultrasonic vibration and powder mixing on EDM, an ultrasonic powder mixing EDM heat transfer model was established based on heat transfer theory, combining ultrasonic and powder mixing characteristics. Based on the established heat transfer model, a transient thermodynamic simulation of the material removal process by ultrasonic powder mixing EDM was carried out, and the accuracy of the simulation results was verified through experiments. The simulation and experimental analysis of the four machining methods, namely, ordinary EDM, ultrasonic EDM, powder mixing EDM and ultrasonic powder mixing EDM, show that the efficiency of ultrasonic powder mixing EDM is 23%, higher than that of ordinary EDM. The addition of mixed powder and the application of ultrasound can reduce carbon build-up on the machined surface and improve surface quality. The addition of the powder mix can make the discharge craters more regular, resulting in a reduction in surface roughness. The average reduction in surface roughness is 8.9%, compared to normal EDM. The average reduction in surface roughness of ultrasonic powder blending EDM compared to normal EDM is 4.3%.