Kinetic of the synthesis reaction of 2-(2, 6-dichlorophenyl)-2, 3-dihydroquinazolin-4(1H)-one in the presence of 2- aminobenzamid and 2, 6-dichlorobenzaldehide has been spectrally investigated. For this purpose, parameters of the reactions were monitored by UV/vis spectrophotometry. Kinetics of the reaction including the effects of the amounts of 2, 6-dichlorobenzaldehide, presence of maltose as a catalyst, temperature, and different polar solvents on the reaction rate were investigated in detail. Rational explanations to account for the unique results, especially for the temperature and solvent effects on the reaction rate, are also provided. A rate law consistent with the observed kinetic data and the proposed mechanism was suggested. In the PH range near or above neutrality imine formation in step2 (rate constant (k2) of reaction mechanism) was a rate determining step, but in the present work in the acidic pH range (formic or acetic acids) rate determining step is step1 (k1) of reaction mechanism, this confirmed based upon the steady state and the solvent studies on the reaction rate. In both solvent, the reaction was enthalpy controlled (ΔH‡ is much greater than TΔS‡), never the less ΔS‡ in the formic acid was less than a mixture of formic acid/ acetic acid, this imply that why the reaction occur more easily in the formic acid.