Main beam supporting leg connecting structure convenient for span adjustment

The utility model discloses a main beam landing leg connecting structure convenient for span adjustment, which comprises a main beam, a left landing leg and a right landing leg, the left landing leg and the right landing leg have the same structure and respectively comprise two branch legs, and the two corresponding branch legs are positioned at the front part and the rear part of the left end or the right end of the main beam; lower protruding supporting parts are arranged on the lower portions of the opposite positions of the upper portions of the two branch legs, supporting extending parts horizontally extending outwards are arranged on the front portion and the rear portion of the upper portion of the main beam correspondingly, the bottom faces of the supporting extending parts abut against the top faces of the corresponding lower protruding supporting parts in a pressing mode, and connecting bases are fixed to the top faces of the two branch legs correspondingly. The upper transverse block is installed o