To provide insights into the chemical composition and functional properties of yak whey powder, in this experiment, native yak whey powder (NYW) from the supernatant of acid precipitated yak milk and sweet yak whey powder (SYW) from waste cheese whey (resulting from enzymatic milk coagulation) for measurement of their total protein, lactose and ash contents, pH values and functional properties such as solubility, water-holding capacity, oil-holding property, foaming capacity, emulsifying capacity and thermal stability. The results showed that the difference between the total protein contents of SYW and NYW was 3.433% which was significant (P < 0.05) while the difference in lactose content was not significant (P > 0.05). The ash content of NYW was 11.188%, which was 3.156% higher than that of SYW, with a significant difference being found between them (P < 0.05). The pH values of NYW and SYW solutions were 4.837 and 5.410, respectively, with the difference being significant (P < 0.05). The difference in solubility was significant (P < 0.05), 34.207% for SYW versus 27.079% for NYW. The water-holding capacity of NYW was significantly higher than that of SYW, but the oil-holding capacity was significantly lower than that of SYW (P < 0.05). The foaming ability, foam stability, emulsifying activity and emulsion stability of SYW were significantly higher than those of NYW (P < 0.05). When NYW and SYW were heat treated at 60 ℃, precipitation began to occur. When the temperature exceeded 75 ℃, the amount of precipitation increased significantly (P < 0.05), and the maximum value occurred at 85 ℃, indicating yak whey powder to be the least stable at 85 ℃. On the other hand, yak whey powder was more thermos-stable commercial Holstein whey powder (HW), the most unstable at 80 ℃. The findings from this study show that the main components and functional properties of the yak whey powders obtained by acid precipitation and enzymatic coagulation are different.