In order to study the water requirement law and dry matter dynamic changes of Cyperus esculentus, Jisha 2 was used as experimental material, and three kinds of soil moisture were set up to carry out bucket planting experiment in shed. The results show that: During the whole growth period, the water requirement of the Cyperus esculentus was low from sowing to tillering stage, large from tillering stage to tuber formation stage, and small at maturity stage.The dry matter accumulation showed a slow increasing trend from seedling stage to tillering stage, a linear increasing trend from tillering stage to tuber formation stage, and a slow increasing trend from tuber formation stage to tuber maturity stage. Comprehensive yield and plant production analysis showed that the medium soil moisture treatment（55%-70% of field water capacity at seedling stage, 70%-85% of field water capacity at tillering stage, 70%-85% of field water capacity at tuber formation stage, 55%-70% of field water capacity at tuber maturity stage） performed better.