Abstract: A three-in-one building fire in Guizhou was taken as the research object. The test was demonstrated by setting the relevant parameters of a real fire case in the FDS software to reconstruct the development process of the fire. The data of temperature and smoke were gotten, which were compared with the patterns of the corresponding parts of the actual fire scene. The fire position and the development process of fire spread were verified. Through the comprehensive analysis of temperature, carbon monoxide concentration slice and fractional effective exposure dose (FED), a reasonable explanation was made for the final death under the combined action of high temperature and smoke. The temperature and CO concentration data were processed, to combine with the empirical formulas and curves, and calculate the death time. The results can help with the fire investigation of similar fire accidents.

Key words: fire investigation; FDS; three-in-one building