本文将杂交问题引入水力机械叶栅设计中，建立了平面叶栅内不可压缩流动Ｂ型杂交问题流函数型的变分原理，并进行了变域变分有限元计算，得到了满足给定的压差分布和厚度分布的叶栅叶型和流场。计算结果表明，本文为平面叶栅叶型的水力设计提供了一种新的有效方法。 In this paper, the problem of hybridization was introduced into the design of hydro-mechanical cascade. The variational principle of the flow function type of incompressible flow B-type hybrid in plane cascade was established. The variational principle of variational variables was obtained. Pressure distribution and thickness distribution of the cascade leaves and flow field. The calculation results show that this paper provides a new effective method for the hydraulic design of plane cascade blade.