The invention discloses a high geogrid with joints formed through injection molding and fusion welding. The high geogrid comprises horizontal strips, longitudinal strips and injection molding bodies, wherein the longitudinal strips and the horizontal strips are intersected to form a net structure, kerfs are formed in each of the longitudinal strips and the horizontal strips at an interval of mesh spacing, holes are formed in one side or two sides of each kerf, the kerfs in the corresponding positions of the longitudinal strips and the horizontal strips are in opposite inserting connection, joints are formed in the inserting connection positions, and the injection molding bodies are arranged around the joints. By means of the structure, the strength of the joints of the geogrid cannot be weakened while the height of the geogrid is increased; the geogrid is high enough, the overall strength of the geogrid is enhanced, soil mass can be better wrapped and constrained, and the reinforcement function on the soil mass is remarkably improved.