α-Capric betaine(α-CB), a new type of zwitterionic surfactant was synthesized by amination of α-chlorododecanoic acid(α-CDA) with trimethylamine(TMA) under hydrothermal condition, and the bothering was that the yield of α-CB was lower caused by the side effect of hydrolysis. Based on the optimal factors such as solvent, feed ratio, etc, the temperature program, a means of kinetic control, was applied to effectively inhibit hydrolysis and thus the yield of α-CB was markedly improved. When kept n(trimethylamine) / n(α-CDA) = 3, 1% of KI as catalyst and 0.5% of α-CB as solubilizer added in advance, the amination proceeded at 70 ℃ for 8 h followed 100 ℃ for 2 h, the yield of α-CB was improved from 62.4% to 92%.