The invention discloses a method for supporting a tunnel roof or a working face roof by using piers. The method comprises the following steps of (1) preparing joist steel or steel channels into cross beams; and (2) fixing a pier on each joint, which is required to be supported, of each cross beam, then sequentially superposing piers on the bottoms of the fixed piers from top to bottom until the cross beams are abutted to the tunnel roof or the working face roof, limiting each two piers in a superposing process, or limiting the piers in a unified mode by serially connecting the piers superposed together with a round bar steel. Moreover, consistency of heights of two sides of the cross beams requires to be kept in a pier superposing process, and a collapse roof is supported by the method. The method is easy to operate, high-altitude operation is not required, and safety is guaranteed.