The influence of microwave on physical and chemical properties of cold and hot-pressed peanut oils was detected. The results showed that unlike the previous reports, the peroxide value of both oils increased firstly with the increase of microwave processing time and power, but decreased with the further increase of microwave processing time and power. The trends of both oils were almost the same. The content of linoleic acid in cold-pressed peanut oil was decreased significantly by microwave processing, but the contents of other fatty acids did not change significantly.