In order to send creatures that damage crops from the environment away with the intent of increasing agricultural throughput, pesticide is applied on farmlands mostly by spraying. There are several ways for spraying pesticide togetger with their possible disadvanteges such as crops may be crushed when using tractor, pesticide droplets may be perfused unevenly when it is applied by a person, or using aircrafts such as helicopter or plane for spraying may contaminate regions surrounding the target area. On account of applying pesticide a cheaper and more efficiently way, it was aimed to use unmanned aerial vehicle (UAV) that is able to fly on and spray farmland autonomously. Accordingly, necessary system components were developed such as an auto pilot system that controls UAV, a ground control station that is used for tracing UAV, and a spraying mechanism. It can be estimated how much time, distance is required and how many refills the UAV needs for a specific farmland before implementing for real by using a developed simulator. Additionally, it was verified that the the equipment to be mounted on the UAV works properly in real time and real world.