The meso-morphology of granite from Shandong Linyi has been observed under the real-time temperature using polarizing microscope LEICA DM4500P. The relations of microstructure morphology with intensity and acoustic emission of granite have been carried on the preliminary discussion by combined with results of axial compression and acoustic emission detection test at different high temperatures. Research results show that the changes of mesostructure and morphology of granite under high temperature are mainly embodied in crack initiation and different propagation speeds at different temperatures. With the increase of temperature, the more internal crack formation and internal damage for granite, and the more frequent acoustic emission activity of granite under uniaxial compression. The mechanical properties and acoustic emission characteristics of granite with the formation of internal crack network of granite has a corresponding relationship. The peak stress curve and ringing cumulative number curve of granite have stable trend when crack expansion is slow. While crack network expansion is rapid, the peak stress curve and ringing the cumulative number curve of granite will appear inflection point and cause mutation. It is expected to infer the change reason of physical and mechanical characteristic parameters for rock in the thermal cracking procedure through observation changes of rock internal structure under heating states.