NOVELTY - Recovering silicon powder from waste cutting mortar of silicon sheet comprises (A) solid-liquid separation of waste cutting mortar, (B) precision separation of liquid containing silicon, (C) liquid flotation, (D) precision filtration, (E) film separation, and (F) acid wash, and (G) vacuum drying. The step (A) involves carrying out solid-liquid separation on waste cutting mortar in continuous operating device to obtain solid precipitate and the liquid containing silicon. The step (G) includes drying semi-dry silicon powder by vacuum drier to obtain silicon powder.    USE - Method for recovering silicon powder from waste cutting mortar of silicon sheet (claimed).    ADVANTAGE - The method can obtain silicon powder with purity of 99.5-99.9%. It overcomes common problems of conventional technology that solid-liquid separation is hard, the purities of products recovered are not high, comprehensive recovery rate is low and recovery process is hard to be perfect. The method is capable of recovering polycrystalline silicon or monocrystalline silicon while recovering polyethylene glycol and silicon carbide from waste cutting mortar of silicon sheet, thus improving regeneration utilization in solar manufacturing industry and meets requirement on clean production.    DETAILED DESCRIPTION - Recovering silicon powder from waste cutting mortar of silicon sheet comprises (A) solid-liquid separation of waste cutting mortar, (B) precision separation of liquid containing silicon, (C) liquid flotation, (D) precision filtration, (E) film separation, and (F) acid wash, and (G) vacuum drying. The step (A) involves carrying out solid-liquid separation on waste cutting mortar in continuous operating device to obtain solid precipitate and the liquid containing silicon, taking solid precipitate as raw material for making silicon carbide, and using liquid containing silicon. The step (B) includes carrying out precision separation on liquid containing silicon from step (A) in continuous operating device to obtain polyethylene glycol and polycrystalline silicon/monocrystalline silicon wet powder, and using polycrystalline silicon/monocrystalline silicon wet powder for next step. The step (C) includes transferring polycrystalline silicon/monocrystalline silicon wet powder to suspending pot and adding prepared flotation liquid, uniformly stirring and mixing, standing for 1-4 hours to obtain silicon-containing suspension rich in silicon powder and precipitate rich in silicon carbide, and using silicon-containing suspension for next step. The step (D) includes filtering silicon-containing suspension by precise filter to remove large-particle silicon and non-silicon foreign matter, and using precisely filtered silicon-containing suspension for next step. The step (E) includes pumping precisely filtered silicon-containing suspension to film separation system, using filter film with proper molecular weight according to process requirement, carrying out film separation, cutting off polycrystalline silicon/monocrystalline silicon substance bigger than molecular weight in silicon-containing suspension by film separation system, and concentrating same, transferring cut-off concentrated wet silicon powder to next step, collecting substance in silicon-containing suspension to reuse for step (C). The step (F) includes transferring wet silicon powder to washing container, adding prepared acid washing liquid to remove silicon oxide layer formed by action of high temperature, washing with acid for 1-24 hours, rinsing washed silicon powder by pure water until pH is neutral, precipitating rinsed silicon powder, centrifuging, and pressing to obtain semi-dry silicon powder for next step. The step (G) includes drying semi-dry silicon powder by vacuum drier to obtain silicon powder.