To investigate the effect of water-binder ratio on the early reaction kinetics of alkali-activated slag， ¹H low-field nuclear magnetic resonance was used to measure the transverse relaxation time of the slag slurry in the first 3 d of alkali-activation and the relative content changes of water in different states. ²⁹Si magic-angle spinning nuclear magnetic resonance， isothermal calorimetry， thermogravimetric analysis and Fourier transform infrared spectroscopy were used to reveal the reaction mechanism of slag alkali-activated at the early stage. The results show that the transverse relaxation time of slag slurry under different water-binder ratio conditions decreases gradually with the alkali-activated reaction， and the movable water is gradually transformed to immovable. After 3 d of alkaline-activation， the high degree polymerization of alkaline-activated products increases with the increase in water-binder ratio. ［AlO₄］^- tetrahedra increase the degree of polymerization and linkage of ［SiO₄］^4- tetrahedra.