By indoor culture,the effect of borax on the change of soil urea,NH+4 N,NO-3 N and urease activity at the application rate of 0%,0.5%,1%,1.5% and 2% borax amount.The results showed that borax could inhibit soil urease activity,and then decreased the urea hydrolysis rate and NH+4 N release rate;the increase of borax dosage more than 0.5% could have more significant effect on the hydrolysis rate of urea and NH+4 N release rate;the borax application had little influence on soil nitrate content.Boron is an essential nutrient element for crop,which can be used as urea slow released agent,showing a good application prospect.