Considering drawbacks such as the low inhibition efficiency and short inhibition life of an existing pure hydrogel, a new physicochemical composite hydrogel inhibitor was developed. First, tea polyphenol radicals were grafted and polymerized onto a hydrogel and then mixed with HNTs (halloysite nanotubes). Electron microscopy, Fourier transform infrared spectrometry and thermal gravimetric analysis were used to analyze the inhibiting effect and mechanism of the composite hydrogel inhibitor. Research shows that (i) the graft copolymerization of tea polyphenols with acrylate will increase the contact area between the grafted gels and the surroundings, thus improving the water absorption capability of the hydrogel; (ii) the added tea polyphenols reduce the content of hydroxyl in coal and the content of carboxyl and carbonyl generated during the oxidation of aliphatic groups and it also increase the content of stable ether bond; and (iii) by absorbing the combustible gases and producing water, HNTs can shorten the exothermic temperature range (From 120.22 degrees C to 572.22 degrees C) of coal sample processed by composite hydrogel, and it can reduce the release of heat, which is 2536.73 J/mg. These results suggest that the composite hydrogel can distinctly inhibit the spontaneous combustion and oxidation of coal, achieving stable inhibition in many aspects such as its physics, chemistry and thermal stability during the whole process of spontaneous combustion.