To explore the effects of different vegetable oils, frying time and frying temperatures on trans fatty acids content in fried flour products,with a view to determining the suitable processing conditions.Methods Palm oil, soybean oil, sunflower oil and hydrogenated palm oil were selected as four kinds of frying oil for flour products. The acid-catalyzed hydrolysis method was adopted to extract oil from flour products. Gas chromatography was used to determine the content of trans-9-octadecenoic acid, trans-11-octadecadienoic acid and trans-9,12-octadecadienoic acid at different frying times and temperatures. Results At lower temperature (160 ℃), the trans fatty acids were not detected in fried flour products with palm oil, soybean oil and sunflower oil, the oil content and trans fatty acid content of fried flour products with hydrogenated oil was significantly higher than the other. On the contrary, the index of palm oil was the best and more suitable as a frying oil. Elevated frying temperature and prolonged frying time would increase the content of trans fatty acids in flour products, and the effect of frying temperature was more obvious. Conclusion Choosing a suitable frying oil, lowering the frying temperature and time would have a positive impact on the content of trans fatty acids in flour products.