To understand the situation of formaldehyde residues in some foods from Guangzhou City, and provide reference basis for risk assessment and government supervise.Methods Food sanitation section had collected 1 416 samples for formaldehyde testing at different times in catering industries, meat markets, supermarkets and wholesale markets. Results The range of content was 2.0-4 500.0mg/kg, 13.21% (187/1 416) of the samples were above 100 mg/kg, and the proportion for poultry by-products was 32.63% (31/95), the proportion for animal by-products was 31.54% (94/298), the proportion for fish (whitebait, harpadon nehereus, fishskin) was 30.85% (29/94), and the proportion for crustaceans (shrimp meat) was 19.35% (24/124). The samples from meat markets and wholesale markets had more formaldehyde than the samples from catering industries and supermarkets. The samples collected from September to November had more formaldehyde than the other months. The samples from 2012-2013 had more formaldehyde than the other years. There was significant difference between different species, different sampling sites, different months and different years.Conclusion Some foods had a high level of formaldehyde contamination, such as animal by-products (omasum, beef heart), poultry by-products (goose intestine, duck intestine), crustaceans (shrimp meat) and fish (whitebait, harpadon nehereus, fishskin). It's relatively more serious from September to November, and the government should strengthen the supervision and prevent foodborne disease.