Cutting and breaking the sunken ship in the deep-sea environment is an important step of salvage. Especially for the deep-sea sunken ship loaded with fuel and liquid dangerous chemicals, safe and efficient cutting and opening is the primary process to remove the dangerous liquid from the sunken ship. This paper expounded technical scheme of ultra-high pressure pre-mixed abrasive water cutting steel plate for 6000 meters deep-sea sunken ship, and introduced the development of 140MPa ultra-high pressure abrasive water cutting equipment integrated into the seabed. The key technologies of ultra-high pressure seawater pump working underwater and seawater lubricated bearing were discussed. The structure and control technology of abrasive mixing valve was analyzed. The cutting head device used together with ROV (remote operated vehicle) robot was also developed. Through the underwater cutting experiment simulated in pool and actual underwater cutting experiment on the seabed, the results shown that this equipment and parameter working conditions fully meet the requirements of sunken ship salvage engineering in deep-sea environment.