By using soil column simulation with machine-planting precision one-time deep fertilization as the background, the effects of fertilization depth on the losses and contents of nitrogen and phosphorus were studied by an experiment conducted in 2019 in the greenhouse of the Experimental Base of Hunan Agricultural University in order to provide a scientific basis for agricultural mechanization. The tested soil is aquic sandy soil (paddy soil), the tested fertilizer was ternary compound fertilizer, and six treatments were set which included CK (no fertilization) and five fertilization depths (0, 5, 7.5, 10 cm and 12.5 cm). The changes of nitrogen and phosphorus contents in ammonia volatilization, field surface water and seepage water as well as nitrogen and phosphorus contents in soil were monitored. Compared with the 0 cm treatment, the accumulations of ammonia volatilization in 5, 7.5, 10 cm and 12.5 cm depth treatments decreased by 68.07%, 82.40%, 99.98% and 99.98%, respectively; total nitrogen in field surface water in 10 cm and 12.5 cm depth treatments decreased by 84.82% and 89.07%, respectively; and the average concentration of total phosphorus in field surface water under fertilization treatments decreased by 92.43%-97.56%. Compared with 0 cm treatmeut, average concentrations of nitrogen and phosphorus in leakage water under different fertilization depth treatments had no significant difference; total nitrogen and total phosphorus contents of 0-10 cm soil layer in 5, 7.5, 10 cm and 12.5 cm depth treatments soil layers increased by 4.63%, 12.25%, 11.85%, 5.69% and 6.40%, 5.90%, 6.09% and 5.43%, respectively. No significant difference existed in nitrogen and phosphorus contents between 20-30 cm and 30-40 cm soil layers. In conclusion, deep fertilization can significantly reduce nitrogen and phosphorus losses, and 10 cm is appropriate fertilization depth for aquic sandy soil.