Acrylamide is formed from reducing sugars and asparagine during the heating, however, the key precursor of acrylamide is not well understood. In order to certify key precursor of the acrylamide, the inhibitory mechanism of p-coumaric acid was studied in low-moisture Maillard model system. The qualitative analysis revealed that the p-coumaric acid most likely reacted with an acrylamide precursor (3-oxopropanamide), yielding 2-(propenamide)coumaric acid. And the ultra-performance liquid chromatography–high-resolution mass spectrometry analysis revealed that the inhibitory rate of acrylamide is proportional to the content of 2-(propenamide)coumaric acid under different condition. Furthermore, the maximum inhibitory rate (82.69%) was observed when 0.1mmol p-coumaric acid was added to an equimolar asparagine-glucose (1mmol each) system upon heating at 160°C for 30min, with a 100μL phosphate buffer (0.1mol/L, pH=8.0). Moreover, the p-coumaric acid also effectively reduced the formation of acrylamide by 66.2% in fried potato chips. So the 3-oxopropanamide is considered to be a possible key precursor of the acrylamide. These observations are important for furthering understanding the formation mechanism of acrylamide.