Appraisal of coal dust explosion was one of the most important test items in coal mine safety inspection agency. Based on the《Appraisal Standard of AQ 1045－2007 Coal Dust Explosion》, appraisal analysis system of large tubular coal dust explosion was used to make experiments of coal samples in different areas for studying correlation of flame length in industrial analysis index of explosive coal samples and identification of coal dust explosion. The results showed that the linear relation of coal dust explosion flame length to volatile dry ash-free basis and dry ash-free basis fixed carbon was obvious, which highly coincided with fitting curves according to analysis data. And fitting formula could provide basic data for laboratory testing data auditing and safety prevention of coal dust explosion.