The inhibition performances of nano-aluminum hydroxide (nano-ATH) foam were evaluated by thermal gravimetric analyzer and cone calorimeter. Results demonstrate that the dry cracking temperature point and ignition temperature point of coal samples increase after nano-ATH foam processing, while the percentage of weight loss decreases. In particular, the dry cracking temperature point increases form 93.2 °C to 164.6 °C, the ignition temperature point increases from 406.9 °C to 443.6 °C, and the weight loss percentage decreases from 34% to 20%. According to the combustion experiment, the peak heat release rate of the coal samples processed by nano-ATH foam decrease from 123.36 kW/m2 of the raw coal to 49.849 kW/m2. Meanwhile, the peak smoke release rate, and the total smoke releasing volume decrease from 0.093 m2/s to 0.006 m2/s, and from 1.027 m2 to 0.574 m2, respectively. Finally, infrared spectral analysis of the coal samples was carried out to investigate variations in functional groups in coals under different characteristic temperatures.