In this paper, based on the kinetic process and mechanism of cement hydration, three basic processes of low alkalinity sulphoaluminate cement hydration are characterized, including nucleation and growth interaction (NG), phase-boundary interaction (I), and diffusion interaction (D). It also studies the influence of water-cement ratio on the hydration exothermic chemical characteristics and kinetic process of low alkalinity sulphoaluminate cement. The results show that the hydration reaction of low alkalinity sulphoaluminate cement is very rapid. The lower the water-cement ratio is, the longer the thermal effect will last. The hydration kinetic process of low alkalinity sulphoaluminate cement is NG–I–D. With a higher water-cement ratio, the hydration kinetic process will transfer from the NG process into I process with a lower hydration degree. And with the water-cement ratio increasing gradually, the hydration reaction from I process to D process is also reduced.