The present invention relates to a multipurpose unmanned air vehicle with an injection nozzle, which is to enclose and protect a rotor of an unmanned air vehicle and store and inject a liquid of agricultural pesticides, decontaminants, a fire extinguishing agent, and a surfactant during unmanned flight. The multipurpose unmanned air vehicle with the injection nozzle also is to supply necessary electricity of the unmanned air vehicle by using sunlight. To achieve the purpose of the present invention, according to the present invention, the multipurpose unmanned air vehicle with the injection nozzle includes: a rotor protection unit installed on the circumference of a side of the each rotor to enclose and protect the side of the each rotor of the unmanned air vehicle and protecting damage to the rotor by preventing a collision between the rotor and an outer subject while forming an inner flow path to suck air to the inside in the upper side and discharge the air to the lower side in accordance with the rotation of the rotor and a rotation space of the rotor； a liquid storing and injecting unit mounted on the inside of a housing of the air vehicle and compressing and storing a liquid including the agricultural pesticides, the decontaminants, the fire extinguishing agent, and the surfactant by individually separating the liquid, wherein the liquid storing and injecting unit individually controls discharge of the each liquid and injects the liquid to the lower side with the discharged air of the rotor through the multiple injection nozzles； and a solar generation unit producing and storing electric power by changing the sunlight to electric energy and supplying the power of a direct current or an alternating current to an each load of the unmanned air vehicle. The multipurpose unmanned air vehicle can reduce noise by absorbing the noise and can prevent the damage to the rotor due to the collision with the outer subject during the unmanned flight and. The multipurpose unm
