Abstract:A field experiment was conducted to study the effect of TU(Thiourea) with different concentration and TU compounding with nitrification inhibitor Dicyandiamide (DCD) and urease inhibitor Phenylphosphoro diamidate (PPD) on urease activities, transformation of urea-N in soil, and corn yield respectively. Incubation test results showed that thiourea and inhibitors combination took on a conspicuous inhabitation on urease activities with a valid inhabitation period being two weeks. TU, TU1+DCD, TU1+PPD markedly inhibited the release of NH4+-N, and its further transformation to NO3--N. As a result, concentration of available-N in soil was affected. Field experiment showed that inhibitors increased corn hundred grain weight and yield markedly. The corn yield could increased 9.14% HT5SS11.49%.