The fire hazard of lithium-ion batteries (LIBs) poses a serious threat to the transport and application. Herein, to investigate the efficiency of low-pressure twin-fluid water mist (TFWM) on suppressing the battery fires. Experiments were executed to research the effect of working pressures and release stages on the fire extinguishing. Aqueous Vermiculite Dispersion (AVD), a commercial agent was specifically designed to extinguish battery fire, was chosen to compare with the TFWM on fire suppression performance under the same condition. The results indicate that the 21,700 LIBs fire could be controlled by applying the water mist within 10 s. Cooling ability with various working pressures (0.4, 0.8, 1.0 and 1.2 MPa) demonstrated an augment in inhibitory effects as the increase of working pressure, and the optimal pressure is 1.2 MPa. The results further show that extinguishing ability of the TFWM is better than AVD agent. When the water mist of optimal working pressure is applied, the surface and flame temperature and concentration of CO have the more significant reductions compared with AVD agent. Therefore, the TFWM is a pretty good candidate to fight the LIBs fire.