Pipe grouting technology is an effective method for the free span of submarine pipes, which has the advantages of good treatment effect, simple operation and  low cost.This paper takes the riser gooseneck free span control project of a platform as an example, and makes detailed introduction of cement bag grouting support technology for submarine pipe free span control. It mainly includes the introduction to cement grouting equipment, technical construction plans, and technical difficulties, providing reference for follow-up readers engaged in related construction operations.