Abstract: We mainly introduced the optimization preparation process and the physical and chemical properties of the lignin diesel fuel. According to the lignin's proportion, the emulsifier content and other influence factors, we used the orthogonal experiment design to optimize experiment. The choice of lignin quantity is 2%, 3% and 4% for total quality, the dosage of emulsifier is 4%, 5% and 6%, HLB is 8.3, 8.8 and 9.3, and the auxiliary emulsifier dosage is 0.2, 0.3 and 0.4 g, respectively. With different level condition as the horizontal standard,we took lots of different ratio of emulsified oil, and finally confirmed the optimal preparation conditions: HLB 9.3, the dosage of emulsifier 6.0%, auxiliary emulsifier dosage 1.2%, emulsifying temperature is room temperature and emulsifying time is 2 min. Simultaneously we also carried on the national standards examination aimed at the oxidized stability, the sulphur content, the acidity, 10% to steam the excess carbon residue, the sheet copper to corrode, the mechanical impurity, the kinematic viscosity, the condensation point, the flash point(closed), the cetane number, the distillation, and the density. All indexes are higher than the GB 252-2000 light diesel oil the national standards. The lignin dieselcetane number arrived at 46.1 and 48.8, which is far beyond the national standard 45. Therefore, this kind of lignin diesel could save energy and reduce pollution obviously. It has great significance to develop the diesel oil substitution fuel, alleviate fuel supply, and cut the specific fuel consumption.

Key words: lignin, lignin discoloration, engine, new energy, lignin diesel, energy saving, orthogonal test