With the accelerated development of agricultural intelligence and mechanization, the traditional premixed pesticide mixing method has been unable to meet people’s needs for safe, environmental and efficient agricultural production. Therefore, an in-depth study on a variety of new pesticide mixing methods has been conducted at home and abroad. The single-stage on-line jet mixing method has been increasingly used because of its advantages of safety and high efficiency, which, however, proved to have some disadvantages such as difficulty in controlling the pesticide mixing ratio and poor mixing uniformity. In this experiment, a set of double-stage online jet mixing apparatus was designed to solve some shortcomings of single-stage online jet mixing apparatus, and the influence of jet nozzle parameters in the main jet mixing apparatus and the radiation flow mixing apparatus on the final pesticide mixing effect were studied for this apparatus, and the most appropriate jet nozzle parameters were selected.