The model barrel experiments were carried out on different drainage methods for the waste mud of bored pile in an engineering project in Wenzhou with the same chemical agent combined with vacuum preloading, the comparison analysis was made on drainage rate, total amount of drainage and water content. The experiments found that with the improved drainage methods, the water content of waste mud is reduced from original 180%～ 190% to 60%～80% in a short time (within 80h), which shows remarkable effect of waste mud disposal by improved drainage methods of additive agent combined with vacuum preloading.