A method for dynamically controlling high-pressure leaching reaction condition of laterite nickel ore includes: setting a target temperature and a target pressure of an high-pressure reactor; obtaining the heat power required for heating the feeding pulp to the target temperature; obtaining the heat power brought by the acid; obtaining a required heat power of a new steam; obtaining a required flow rate of the new steam; adjusting a real-time flow rate of the new steam to the required flow rate of the new steam, adjusting an exhaust valve opening degree and a discharge flow rate of the high-pressure reactor to make the real-time pressure of the high-pressure reactor equal to the target pressure，adjusting the flow rate of the new steam to make the real-time temperature of the high-pressure reactor equal to the target temperature. The beneficial effect of this disclosure is: the reaction condition of the high-pressure leaching reaction is initially determined according to the feed condition, and then the reaction conditions are adjusted according to the real-time temperature and pressure of the high-pressure reactor. Through the cooperation of the above-mentioned two control modes, the temperature and pressure of the high-pressure reactor can be maintained under an optimal temperature and pressure condition, thereby improving a leaching efficiency of laterite nickel ore.