［Purposes］ The paper aims to solve the problem of lack of quantitative index expression in current deflagration terrain extraction methods.［Methods］ Based on the advantages of digital terrain analysis technology in the expression of terrain features, the key deflagration terrain feature expression scheme taking topographic position index, slope and surface curvature as quantitative indexes was proposed, the extraction method and process of deflagration terrain based on grid digital elevation model(DEM) were established, and Liangshan fire area was selected as the test area for deflagration terrain extraction experiment.［Findings］ The method effectively extracted four types of deflagration terrain in Liangshan fire area, namely canyon, ridge, steep slope and ditch pond meadow, the deflagration terrain area is 25.78 km². Considering the effect of resolution of grid DEM on the extraction results, the data with resolutions of 5, 15 and 30 m were taken for experiments, and the corresponding deflagration terrain areas were 25.17, 25.51 and 25.78 km², respectively.［Conclusions］ There are differences in deflagration terrain extraction results of grid DEM with different resolutions.