The invention provides a liquid explosive-based explosive composite pipe manufacturing process with a negative pressure cavity, which includes: coaxially installing the cladding pipe and the base pipe on the soft base from the inside to the outside, and according to the Calculate the amount of explosives according to the specifications, and install the inner tube to adjust the water column, use the sealing ring to seal the upper end of the annular cylindrical gap between the covering pipe and the base pipe, and use a vacuum pump to pump the annular cylindrical cavity into a negative pressure and seal it , place the assembled tube blank coaxially with the container and inject liquid explosives, and detonate the explosives to obtain metal composite tubes. The invention can greatly improve the production efficiency; the charge is uniform, the combination rate of the composite pipe is high, the welding quality is good, no constraint mold is required during the welding process, the production cost can be greatly reduced, and the circular cylindrical cavity is pumped into a vacuum pump. Negative pressure greatly reduces the influence of air on explosive welding, which not only improves the bonding quality of composite pipes, but also reduces the amount of explosives used.