The world energy resource mainly depends on the fossil fuel, but it will be used up in tens of years. On the way to search renewable and environment-friendly energy resource, the biomass has been utilized for many years, but the corresponding problems including the thermal efficiency and pollution need to be resolved. At the present time, LPG (major components are propane and butane) has a great potential to be utilized and with less exhaust pollutants. This paper focuses on applying the propane gas and wood powder to form mixed fuel flame. As a fundamental research, two experiments are carried out to investigate the soot particle behaviors. One is the soot particle diameter measurement by Gmie's light scattering theory, the results show that the soot particle diameter of the mixed fuel flame is greater than that of the propane gas flame. Another is the soot particle density measurement by weight difference method. The results show that the soot particle density of the mixed fuel flame is greater than that of the propane gas flame. The experiments make clear that the wood powder can be applied to form a mixed fuel flame with propane gas
