A growing product on the worldwide dairy market is ultra-high temperature (UHT) milk, which can be kept at room temperature for 6 to 9 months. As the milk undergoes either direct or indirect UHT treatment at 140 ℃ for a few seconds, could kill the majority of bacteria and heat-resistance enzymes. The whey protein in milk will experience a series of physiochemical reactions such as denaturation, proteolysis, age gelation, sedimentation and Maillard after UHT treatment and following storage. The aims of this review were to screen occurred reactions in whey protein, allocate the generated flavor and analysis the volatile compounds. This review explained the mechanisms of the physiochemical reactions, and analysed the related flavor and relevant compounds of the flavor. Also, proposing several suggestions to improve UHT milk quality and find out suitable treatment conditions to prevent or minimize the effects of UHT on whey proteins.