A growing number of agricultural applications focus on copper nanoparticles (Cu NPs) because of their multifunctional qualities and many unique characteristics. This chapter covers the application of copper nanoparticles (Cu NPs) in the agrochemicals field for releasing pesticides and fertilizers and providing efficient delivery. The use of agrochemicals at extreme levels and for a long time may harm the soil system. Additionally, they have strong antimicrobial properties that inhibit the activities of soil microorganisms so that they may be harmful to the soil's health and the microorganisms crucial to the operation of both terrestrial and agroecosystems. Therefore, it is essential to understand the effects, use, and mechanism of action of copper nanoparticles (Cu NPs) on soil processes, soil microorganisms, plants, and their distinctive nano-specific properties. This chapter reviews the most recent research on the possible effects of copper nanoparticles (Cu NPs) on the soil–plant ecosystem in the agriculture field. It gives readers a comprehensive grasp of the copper nanoparticles in the soil–plant ecosystem. This chapter explores the extensive use of copper nanoparticles in agriculture, their potential interactions with different soil constituents, and their effects on variables. This chapter also explores how plants absorb, move and distribute them across various exposure and extreme conditions. This chapter summarizes that several variables such as pH, types of soil and organic matter concentration control and affect the solubility, bioavailability and biotransformation of copper nanoparticles (Cu NPs) in the soil–plant ecosystem. Other factors, such as contaminants, environmental conditions, and time intervals, may also affect their soil toxicity and biotransformation.