The invention relates to a triangular unit block of a metal truss antenna cover and a manufacturing method of the triangular unit block, and aims to solve the problems of low intensity and low reliability of a film material in the existing metal truss antenna cover due to fixed connection. The triangular unit block of the metal truss antenna cover consists of a triangular metal framework, connection corner fittings and the film material; ribbed plates of the triangular metal framework are formed by extruding an aluminum alloy material, and the three ribbed plates are welded into a triangular structure through a welding process; during manufacturing of plates, pressure is applied to the upper portions of the connection corner fittings to press the film material below the connection corner fittings on the triangular framework; and then the connection corner fittings, the metal framework and the film material are locked into a whole according to an assembling relation between the connection corner fittings and the metal framework and are fixed through limiting locking films. When the manufacturing method is used for manufacturing the triangular unit block of the metal truss antenna cover, no large-sized hydraulic equipment is adopted to lock the connection corner fittings, so that the production investment is reduced.