The method of using ultrasonic heating to aid high precision moulding of micro features has been studies. The study developed a method of using ultrasonic vibration to heat the polymer and hot embossing high precision micro features. A commercial ultrasonic welding machine is converted to provide the heating of polymer and mold then into precision micro features for study of ultrasonic heating and the microflow of polymer under ultrasonic agitation. A stainless steel microporous mold of 200µm thick with through holes of 50µm and 200µm in diameter were used. Using a frequency of 35kHz, the microflow behavior of PC (Polycarbonate) and PE (Polyethylene) in the microchannels were investigated. The differing properties of microflow for these two types of polymer give indication on the theoretical and practical agreement on prediction of microflow under ultrasonic energy.