In　order　to　investigate　the　mechanism　of　the　forward　and　aft　cascades　performance　changes　at　different　percent　pitches,　a　series　of　tandem　cascades　were　designed　according　to　Lieblein　factor.　The　tandem　cascades　were　simulated　at　six　different　percent　pitches.　On　this　basis,　the　forward　and　aft　blade　stacking　lines　of　a　tandem　cascade　were　curved　to　analyze　the　influence　of　the　spanwise　non-uniform　percent　pitch　on　the　performance　of　tandem　cascade.　The　results　showed　that　the　expansion　of　cascade　passage　and　pressure　distribution　changed　with　the　variation　of　the　percent　pitches.　The　load　of　forward　blade　increased　while　the　load　of　aft　blade　decreased　with　the　rising　percent　pitch.　Compared　with　original　cascades,　the　total　pressure　loss　coefficient　decreased　both　at　forward　and　aft　blades,　the　total　pressure　loss　coefficient　of　T5　blade　decreased　51.3%　at　80%　percent　pitch.　The　incidence　angle　range　of　tandem　was　influenced　by　forward　cascades;　the　positive　incidence　angle　range　increased　with　rising　percent　pitch.　Corner　separation　of　aft　cascades　decreased　while　the　percent　pitch　increased.　The　total　pressure　lose　coefficient　decreased　14.5%　when　the　tandem　cascades　were　positively　curved.　The　total　pressure　loss　coefficient　decreased　15.6%　and　55.2%　when　the　forward　blade　was　negatively　curved　or　the　aft　blade　was　positively　curved　while　the　other　blade　kept　straight.　©　2018,　Editorial　Department　of　Journal　of　Aerospace　Power.　All　right　reserved.