Abstract: In view of the field joint structure and construction requirements of glass microsphere syntactic polyurethane (GSPU) deepwater insulation pipes, a set of 3-valve type pouring mold that can open and close automatically driven by pneumatic cylinders is designed. In order to improve the quality of field joint installation as well as mold practicability, the structure is improved and optimized correspondingly. Based on this designing scheme, a physical mold is manufactured and then the pouring test is carried out using the mold. The results show that this pouring mold, to some extent, is able to improve the field joint installation quality while guaranteeing the construction efficiency of field joint installation. Besides, the material and personnel investment is reduced, lowering the composite cost for field joint installation.