Aiming at the problems of difficult treatment of silicon sludge produced during silicon removal from steam injection thermal recovery sewage in Liaohe oilfield，and formation deficit and inter-well steam channeling in the later stage of heavy oil steam injection development，a kind of temperature-resistant and high-strength silicon sludge ceramsite was prepared by granulation and sintering treatment with waste silicon mud as raw material，and prepared with polymer solution to obtain silicon sludge ceramsite plugging agent. The effects of silica sludge content and sintering temperature on the compressive strength and apparent density of silica sludge ceramsite were investigated through single factor experiments，and the hydrothermal stability，suspension and blocking properties of the plugging agent were evaluated. The results showed that the apparent density of silica sludge ceramsite was＞ 2.25 g/cm³，the compressive strength of silica sludge ceramsite was ＞14 MPa and the temperature resistance was 350 ℃under the conditions of 60% silica sludge doping and 1180℃ sintering temperature. The settlement rate of silica sludge ceramsite in the polymer solution with a mass fraction of 0.3%—0.5% was lessthan 0.0075 m/min，and the high temperature plugging rate was higher than 82%，which could meet the performance requirements of plugging，channeling and filling formation deficit in heavy oil thermal oil reservoirs in Liaohe oilfield. At the same time，the discharge of pollutants from silicon sludge in oilfield could be reduced by preparing ceramsite from silicon sludge produced by silicon removal from produced sewage and reusing in oilfield.