Abstract: A net assembly used for purse seine fishery, which is mounted on a first vessel, dropped into seawater from the first vessel, and towed by a second vessel to surround and pull fish to capture fish. The net assembly includes a plurality of floats floating on a surface of seawater to provide buoyancy to the net assembly, and coupled to one another in a spaced manner in a lengthwise direction of the net assembly; a net combination of a plurality of nets disposed under the floats in an inter-coupled state, and sunken and deployed from the surface of seawater to surround and capture fish; a weight body extending along a lower end of the net combination to provide a sinking force by means of gravity to sink the net combination; and a purse wire extending along the net combination while being spaced apart from the weight body in a downward direction, and tightened by the first vessel to allow the net assembly to form a closed space below the surface of seawater.