Activation properties analysis of spontaneous combustion coal gangue was carried out after selecting, crushing, milling and sieving the coal gangue. X ray fluorescent spectrometey(XRF), inductively coupled plasma atomic emission spectrometry(ICP AES), X ray diffraction(XRD) and thermal analyzer were employed to analyze the effect of different mineral and different composition on activation properties, and compressive strength testing was employed to test the activation properties of spontaneous combustion coal gangue. The results indicate that the active substance in spontaneous combustion coal gangue is amorphous SiO2, amorphous Al2O3 and κ Al2O3; the activation properties are improved with decreasing crystallization rate; and the activation properties are affected by the structure loose ratio. The activation properties can be quickly tested through the solution of Si4+ and Al3+, or the crystallization rate determined by XRD.