Amidinothiourea (ASU) is an important nitrification inhibitor, which effectively prevents ammonium nitrogen from being oxidized to nitric nitrogen by inhibiting the activities of Nitrosomonas sp and Nitrobacter sp in soil, thereby reducing nitrogen loss. Nitric nitrogen is easily lost by water, resulting in nitrogen loss, which not only reduces the utilization rate of nitrogen fertilizer, but also may migrate to water through leaching, resulting in environmental pollution. The use of nitrification inhibitors such as amidinothiourea can reduce the formation of nitric nitrogen at the source, improve the utilization efficiency of nitrogen fertilizer, effectively increase crop yield, and reduce the negative environmental effects of nitrogen. Therefore, as a nitrogenous fertilizer synergist, guanidine thiourea has shown good yield increase effect in agricultural production, which not only helps to increase crop yield, but also reduces the pressure on the environment of nitrogen fertilizer use to a certain extent, and provides support for sustainable agriculture.