Abstract: The effects of cooking utensils,temperature,time and food on the quality of edible vegetable oils used in frying food were studied by orthogonal experimental design.Indices for determination were acid value and carbonyl value.The results showed that the effects of cooking utensils,temperature and time on the carbonyl value were significantly,and that the effects of cooking utensils,temperature and food on the acid value were significantly.The quality of 50 oils used in frying food in Gungzhou were determined and 18 oils were not up the standard of food hygiene in China,the rate was 36%.