Sugar-rich foods could generate large amounts of furfural and 5-hydroxymethylfurfural during thermal processing.During these different processes,the contents of furfural and 5-hydroxymethylfurfural were also different in foods.When the contents of furfural and 5-hydroxymethylfurfural exceeded a certain limit,it would harm human health.In this paper,the mechanisms,determination methods and safety of furfural and 5-hydroxymethylfurfural have been reviewed.