The accuracy of fertilization position is an important aspect affecting the performance of variable rate of fertilization (VRF) applicator.Aiming at the problem of position lag in VRF,on the basis of existing research, with the goal of improving the operation accuracy of VRF, a lag time detection system was built by using pressure sensor, ArduinoUNO and other equipment which could detect, show and save the lag time date, and the relationship model between fertilizer dropping time and its influence factors was established. Based on the relationship model between factors, a method of fertilizing position correction based on lag distance was proposed based on the data. This method used the lag time and the operating speed to calculate the lag distance. When the distance between the machine and the grid boundary was equal to the lag distance, the fertilization state was changed to realize the correction of the fertilization position. Based on the lag time measured in the field experiment, the lag time detected under different states (static and dynamic) and different rotating speeds of the variable rate fertilizer applicator was analyzed, and the field lag correction experiment of the variable rate fertilizer applicator was carried out. Field experiment results showed that the detection accuracy of the lag time detection method proposed was not less than 84.1%; The established speed-lag time model can accurately calculate the lag time, and using the fertilization position correction method based on the model, the fertilization position correction experiment was carried out at the same vehicle speed (4.25km/h) and different motor speeds, and the fertilization position lag distance was reduced by at least 61.8%. The method proposed can effectively improve the lag of fertilization position of VRF applicator and meet the requirements of field work.