The invention provides a load control method and device of a facility agriculture DC power supply network. The method comprises the following steps: obtaining the unit capacity, the load stable powerand the instantaneous impulse power of each load type of the facility agriculture DC power supply network; the load type comprises constant voltage load and constant power load; determining the integral time constant and proportional coefficient of the load type PI controller according to the unit capacity, the load stable power and the instantaneous impulse power; and determining the PI control model of the load type PI controller according to the integral time constant and the proportional coefficient, and achieving the load control according to the PI control model. The embodiment of the invention obtains the integral time constant and the proportional coefficient of the load type PI controller through the unit capacity of each load type, the load stable power and the instantaneous impulse power, realizes the parameter tuning of the PI controller, and thus realizes the load control in the facility agriculture DC power supply network.