Water Chestnut were stored and processed by Freeze-drying. Eutectic point and consolute point were measured by resistivity method. The main factors affecting the properties of freeze-drying product and production capacity of the equipment were studied using L12(35) orthogonal experiments. Water content of product, product form, rehydration character were evaluated. The optimal technics for freeze-drying Water Chestnut were following: deep freeze temperature -36℃, deep freeze time 20h, pressure of drying room while vacuum sublimation drying (120±10)Pa, pressure of drying room while vaccum resolution drying (40±10)Pa, shelf temperature while vacuum resolution drying 50℃, drying time 14h.