Abstract: After looking back on the progress and present status of synthesis of gold nanoparticles (nano-Au), its optical properties and functionalization, and principle of the nano-Au colorimentric sensor, a review on the application of the nano-Au colorimetric sensor to the safety examination of foodstuffs during the last decades was given, relating especially to the domains of determinations of heavy metal ions, DNA, pathogenic bacteria, residual pesticides, residual antibiotics and other drugs, toxic and harmful chemicals, and mycotoxins in food. And a brief prospect of future progress in this field was also given (59 ref. cited).