The gel properties and molecular forces of the Aohan Merino lamb myofibrillar protein (MP) were investigated during heat induction at different pH levels. The effects of pH values (from 5.0 to 8.5) on the lamb MP gel textures and water-holding capacities were analyzed. The protein gels had the lowest water-holding capacity and a disordered microstructure at pH 5.5 (P<0.05) and had the lowest level of hardness at pH 6.5 (P<0.05). The hardness and water-holding capacity were found to be the highest at pH 8.0 (P<0.05), which coincided with a compact and ordered microstructure. At these three representative pH values, hydrophobic interactions were the main forces that were observed during gel formation, but the pH level also influenced the formation of ionic and hydrogen bonds. Different mechanisms of gel formation were therefore observed at different pH values. In conclusion, the formation of heat-induced gels with different properties was a result of the dominant molecular forces that are regulated by pH. These findings provide a theoretical basis for the innovation of heat-induced gel lamb products. (C) 2014 Elsevier Ltd. All rights reserved.