The passive control method of  bionics dimple  surface structure wa  adopted to explo re fiv e dim ple sc heme s with different depths, which were 0. 10 mm, 0. 15 mm, 0. 20 mm,  0. 2 5 mm  and 0 . 30  mm re sp ectively.  The  depth dia me ter ratio was 0. 25, and three rows of dimples were arranged at 18% ~30% ch ord lengt h,  in w hich th e di st ance f rom  the  suctio n and pre ssur e s urface s of t he blades was 2 mm, and the ax ial spac- ing was 4 m m. Th e re search ob ject was the plan e ca scade compose d of 1+1 / 2 hi gh press ure transoni c tur bine. The aero- dynamic in dexes such as loss coefficient and st atic pressure dist ribu tion were o btained b y com merc ial CF D si mulation, and the influen ce of dif feren t depth pit s on the flow p erform- ance of t urbi ne c asca de wa s an alyze d. The nu meric al r esults sho w that the 0. 2 mm deep e nd wall pi t has th e best flow con- trol effe ct o n the d evelopmen t of v ortex syst em in the channel,  inhibits th e lateral seco ndary flow clim bing alon g th e span wise directio n, w eake ns the sho ck in tensity nea r th e en d zone, and reduces the total pressure loss coefficient of the cascade by 2. 71 %.