The trans fatty acids content and quality of sunflower oil bought from market was determined and compared with the oil from individual workshop. The results showed that total content of trans fatty acids of 7 samples, out of the total 26 samples, were above 1%, 1 above 2%, and most of them were fully refined oil, which indicated that excessive processing brought the rise of trans fatty acids content. The oil from individual workshop expressed with low degree processing, quality was lower than advanced refined oil with high degree processing. The acid value of 23.1 % samples and peroxide value of 42.3% samples were not in conformity with the national standards. The failure rate of the sample was 76.9%. The inhabitants who often buy oil in bulk need to pay attention to the quality, safety and health of the oil.