samples of raw materials used for chafing dish by 29 restaurants were tested.The results showed that 35(35 4%) samples were formaldehyde positive.The positive rate of dried squid soacked with water was 75%.The positive rate of dried rolls of bean milk cream was 66 7%.17(58 6%)chafing dish restaurants were found using formaldehyde in the processing of raw materials.The result of the survey suggests that the food hygiene inspection and surveillance should be strengthened,more attention to food hygiene training should be paid for the restaurant operators,formaldehyde should be substituted by some new harmless food additives for the processing of raw materials used in chafing dish.