Trypsin hydrolysis is an effective method to produce functional liquid egg yolk. Pasteurization is necessary for microbiological safety in liquid egg production. This study investigated the effects of different heat treatments （60， 64， 68 ℃ and 72 ℃， 4 min） on the functional properties and thermal stability of liquid egg yolk hydrolyzed with trypsin. The results showed that functional properties of liquid egg yolk hydrolyzed with trypsin， such as emulsifying activities and emulsion stability， protein solubility， the water absorption capacity and the oil absorption capacity， foaming capacity and foam stability， were significantly higher （P < 0.05） than that of liquid egg yolk without trypsin hydrolysis. Emulsifying activities， protein solubility and foaming capacity of liquid egg yolk with/without trypsin hydrolysis showed significantly decreasing with the temperature increasing. The result of SDS-PAGE illustrated that trypsin hydrolysis could obviously change the distribution of protein molecular weight in liquid egg yolk， and higher temperature heat treatment （68 ℃ and 72 ℃） resulted in significant protein aggregation. Fourier transform infrared spectroscopy results confirmed that trypsin hydrolysis and heat treatment had a significantly effect on egg yolk -OH functional groups.