To investigate the effect of various cooking methods on content of total polyphenol and flavonoids in vegetables, six kinds of vegetables, onion, celery, leek, spinach, cabbage and tomato, were respectively cooked by ways of quick–frying, blanching, boiling and microwave cooking. The total polyphenol content was determined by folin- ciocalteu method and total flavonoids by aluminum chloride chromogenic method. Indicators of the reserving rate, transferring rate and actual loss rate were employed to discuss the effect of different of cooking methods on polyphenols and flavonoids content. Results showed that the content of total polyphenols and flavonoids in vegetables decreased obviously with boiling, polyphenols loss in tomato was about 42.14%, and flavonoids loss in leek and in spinach were both above 40%. Polyphenols and flavonoids were partly transferred to soup after microwave cooking and blanch, the transferring rate of flavonoids were above 35%. The reserving rate of polyphenol remained high with quick–frying, there were less than 10% of polyphenols loss in onion, leek and spinach. Total polyphenols and flavonoids were declined after heat cooking, which might make them decomposed under high temperature. Polyphenols and flavonoids in vegetables could be kept to their maximum by quick–frying amongst the four approaches.