Abstract: The objectives of this study were to evaluate the effects of 100%, 80% and 60% microwave power at the endpoint temperature of complete denaturation of the protein on heat loss, texture and microstructure of Longissimus muscle of yak meat by SDS-PAGE, heating loss rate, texture analysis and paraffin section. The results showed that in a constant microwave power, heating loss rate and the shear forces increased with the extension of the microwave heating time (p<0.05), muscle fibrils appeared larger clearance and were broken seriously;heating loss rate of 80% microwave treatment were higher than 60% or 100% (p<0.05), and shear force in 60% treatment were higher than in 80% or 100% (p<0.05). The results suggested that the low-fire microwave processing was better for yield, tenderness and microstructure of yak meat when the heating time was constant, but large microwave power heating and short time schedule should be chosen to obtain better quality of yak meat.