GPJ01-B type cable splice box is designed according to arc shape. On the opposite side, the clamp structure is adopted. It is convenient to install. The installation can be completed by inserting four oblique slots and tightening four stainless steel screws. It will bring great convenience to the repeated opening and use of the expansion increment of optical cable in the future, and greatly improve the construction efficiency. Because the four oblique inserts and the main body of the cable joint box are made of engineering plastics with the same formula, the shrinkage and expansion coefficients are the same under different temperature environments, and the variation is the same, so the cable joint box has high reliability and sealing performance.