With different aromatic amines as raw material, 1, 2-dichloroethane as solvent, different aromatic isocyanates were synthesized by solid phosgene method. Then romatic isocyanate and different aromatic amine reacted to form four kinds of different aromatic urea. The physical constants, UV and IR of the four kinds of aromatic urea were determined respectively, and they were identified as target compounds by systematic spectral analysis and study. Through determining the plant growth activity of the aromatic ureas on towel gourd, it is found that these compounds have good activity as plant growth regulator.