Abstract: There are many existing security risks of buildings in the new backfill pit. By using the grouting technologies to reinforce density,uniformity and bearing capacity, we can produce large settlement and uneven settlement in order to problem of negative skin friction of pile, and through the prestressed concrete pipe to test grouting effect in and outside the pit. The results showed that, the character of fill is improved obviously after grouting reinforcement. So, using grouting technology to treat fill is reasonable.