A lighting system comprising: a first reflector and a second reflector facing each other; at least one light source module disposed between the first reflector and the second reflector; an optical member disposed at a predetermined distance opposite to the second reflector; a first cover representing a bottom cover with the second reflector disposed on an upper surface thereof and being coupled to and supporting the optical member; and a second cover representing a side cover laterally coupled to the first cover to support the light source module and having the first reflector located on a lower surface thereof; a third cover representing a top cover coupled to both the first and second covers (300, 500), wherein the first cover includes: a bottom plate; first lateral plates disposed to face each other with respect to a width direction of the bottom plate;second lateral plates disposed to face each other in a lenght direction orthogonal to the width direction and supporting the optical member; and a plurality of pins arranged on an upper surface of the bottom plate to further support the optical member, and the lower surface of each pin, which comes into contact with the second reflector, has a greater area than the upper surface of the pin, and wherein the first cover includes: a first coupling portion disposed at a lower portion of each first lateral plate; a second coupling portion disposed at an upper portion of each second lateral plate to couple with the optical member; and a third coupling portion disposed at a lateral portion of each second lateral plate; wherein the second cover includes: a fourth coupling portion located at a lower surface of the second cover so as to be coupled to the first cover; and a fifth coupling portion located at a lateral surface of the second cover so as to be coupled to the third cover; wherein the third cover includes: sixth coupling portions located at opposite sides of the third cover so as be spaced apart from one another in the length direction of the bottom plate; seventh coupling portions located at opposite sides of the third cover so as to be spaced apart from one another in the width direction of the bottom plate; and eighth coupling portions arranged at a lower surface of the third cover so as to be coupled to the second coupling portions of the first cover. a first reflector and a second reflector facing each other; at least one light source module disposed between the first reflector and the second reflector; an optical member disposed at a predetermined distance opposite to the second reflector; a first cover representing a bottom cover with the second reflector disposed on an upper surface thereof and being coupled to and supporting the optical member; and a second cover representing a side cover laterally coupled to the first cover to support the light source module and having the first reflector located on a lower surface thereof; a third cover representing a top cover coupled to both the first and second covers (300, 500), a bottom plate; first lateral plates disposed to face each other with respect to a width direction of the bottom plate;second lateral plates disposed to face each other in a lenght direction orthogonal to the width direction and supporting the optical member; and a plurality of pins arranged on an upper surface of the bottom plate to further support the optical member, and the lower surface of each pin, which comes into contact with the second reflector, has a greater area than the upper surface of the pin, and a first coupling portion disposed at a lower portion of each first lateral plate; a second coupling portion disposed at an upper portion of each second lateral plate to couple with the optical member; and a third coupling portion disposed at a lateral portion of each second lateral plate; a fourth coupling portion located at a lower surface of the second cover so as to be coupled to the first cover; and a fifth coupling portion located at a lateral surface of the second cover so as to be coupled to the third cover; sixth coupling portions located at opposite sides of the third cover so as be spaced apart from one another in the length direction of the bottom plate; seventh coupling portions located at opposite sides of the third cover so as to be spaced apart from one another in the width direction of the bottom plate; and eighth coupling portions arranged at a lower surface of the third cover so as to be coupled to the second coupling portions of the first cover.