Pesticides are toxic chemicals or mixtures of substances or biological agents that are intentionally released into the environment to prevent, control, and/or kill pest populations. The resistance of pesticides to biological, chemical and photolytic degradation leads to their accumulation with undesirable consequences in the environment. The aim of this research is to develop a suitable catalyst for the photochemical degradation of the model component of insecticides. The insecticide acetamiprid (C10H11ClN4), which occurs as a component of the commercial product Mospilan, was used as the model component. The study was carried out in a plate photoreactor with recirculation of the reaction mixture using an immobilized photocatalyst layer (TiO2). The effect of initial pH of the reaction mixture on the efficiency of photocatalytic degradation of acetamiprid under the conditions of simulated solar radiation was investigated. The efficiency of photolytic and photocatalytic degradation of acetamiprid was also compared by determining the change in acetamiprid concentration using high performance liquid chromatography. An abrasive substrate was used as a support and the mineral binder Procol was used to prepare the immobilized photocatalytic layer. It was found that the photolytic reaction leads to a slight decomposition of acetamiprid under simulated solar irradiation. The photocatalytic degradation of acetamiprid under simulated solar radiation is most effective at pH = 4.5-6.5. It was also found that the photocatalytic degradation of acetamiprid was more efficient when the reaction mixture was pretreated with ultrasound for 15 minutes. The results of the kinetic analysis showed that the photocatalytic degradation of acetamiprid under the conditions used in this work can be described by a simple first-order kinetic model.