A pesticide / fertilizer applying device comprises a pesticide / fertilizer container, a pesticide / fertilizer conveying pump, a conveying pipe, a pesticide / fertilizer applying switch, a pesticide / fertilizer applying rod, a pesticide / fertilizer applying nozzle and a quantitative pesticide / fertilizer applying control circuit module, wherein the whole device is powered by a storage battery mounted at the bottom of a pesticide barrel; the quantitative pesticide / fertilizer applying control circuit module controls start, stop and rotating speed of a miniature diaphragm pump according to a preset work mode; a water pump is connected with the conveying pipe and the nozzle, and different spraying effects can be realized by replacing different nozzles so as to adapt to different spraying applications. With adoption of the pesticide / fertilizer applying device, application of rooting fertilizer water, a fertilizer solution, pesticide and a bud inhibitor can be integrated, the device is portable, simple and convenient to operate and use, adopts a digital intelligent control technology, can guarantee precise application of the fertilizer, the pesticide and the bud inhibitor, and realizes precision work; high benefits and low cost are realized, the labor intensity for manual work of fertilization and pesticide application can be reduced, the working efficiency is increased, the material and labor costs are reduced, and remarkable economic and social benefits are realized.