The quality of cleaning and the cleaning efficiency of underground diaphragm wall beam joints directly affect the water retaining effect and construction progress of diaphragm wall. The traditional wall brushing method is trivial, low efficient and with bad effect and high requirement. The improvement and development of steel brush and installation of wall brushing device are carried out. The wall brushing device is connected on the scraper bucket grooving machine frame. As a result, good effects have been achieved.