High water content silt in urban dredging and construction process has high liquidity typical characteristics which may lead to extremely inconvenient in transport and turnover. Carrying out the experimental study of decreased flow ability of silt by using high water absorbent material. The results show that flow ability of silt increased with moisture content rise, the mathematics model of flow ability and moisture content is got from the curve fitting of the test results which is quadratic function. A little cost of high water absorbent material can obtain the good effects on decreasing silt flow ability to an appropriate level that is very conducive to transport and turnover. The net flow value is introduced to quantitatively describe improvements of silt’s flow ability caused by high water absorbent materials. The net flow value of silts with different initial water contents would reduce at an identical ratio level when added high water absorbent material. The result for decreasing flow ability by adding high water absorbent material is immediately obvious. In the case of low mixing uniformity with high water absorbent material and silt, the decreased flow value of silt is close to optimum. Mixing duration and intensity have little Impacts on the flow ability of the silt. Time consuming and work intensity would reduce obviously when it’s taken to engineering application.