The invention discloses a method and a device for producing water dispersible granules of pesticides by an extrusion method. Aiming at the characteristic of materials which are changeable in shape in a production flow, the production flow of a WG (working group) is recombined based on workshop sections, and technical groups similar in the material shape and a transmission mode are combined in sequence to form a workshop section; a continuous and sealed production line is adopted, pesticide raw materials are taken as a starting point, and the continuous and sealed production line comprises four main workshop sections of mixing, smashing, mediating and prilling, drying and screening, and tail gas purifying; and manual operation in a batch-type workshop production line is discarded in joining and linking processes among the workshop sections, so that the production efficiency is greatly increased, the stability of quality of different batches of products is ensured, and meanwhile dust overflow in the production process is restrained, the labor environment is remarkably improved, the labor intensity is reduced to a great extent, and the labor employment is reduced by over 50%.