Abstract: High pressure water washing technology has been widely applied in the field of the decommissioning of nuclear facilities, and it is used to wash the sump for craft conveyance, the craft workshop, the hermetic sump, and some other nuclear equipments as well. We have got a set of technical data correlated with high pressure water washing technology by comparing the situations between the test before and after the washing work. At the same time, we also improve our technique on some special cases, which made the high pressure water washing technology more prefect in the field of the decommissioning of nuclear facilities.