Aluminum urea chloride complex was easily synthesized by microwave irradiation from mixed solution and it was used as a precursor for further process. The complexes have proved that urea molecules constructed a coordination sphere around the aluminum atom and formed a stable structure with microwave irradiation. Molar ratio between urea and aluminum chloride was an important factor for the synthesis of AlN particles. After microwave irradiation to the solution with molar ratio (urea/Aluminum chloride) above 6, AlN particles without Al2O3 were formed from aluminum urea chloride by heat treatment at 1000 in nitrogen atmosphere. AlN particles with low oxygen content of 0.85 wt% were successfully synthesized at 1700 under N2 atmosphere in the molar ratio of 6.