Abstract: Described is the working principle of the high-pressure spray water system for steel tube surface descaling. Analyzed are the problems of the equipment affecting the high-pressure spray water descaling efficiency. Discussed is the chemical mechanisms of tube surface rusting. The rusting is solved by means of the modified oil inlet sealing type of the machine crankshaft with the high-pressure check valve design,and small-sized nozzles as determined via experimental comparison. As a result,tubes can be well descaled,and at the same time no surface rusting produced.