Abstract: 1n the experiments of a plane compressor cascade, use of partition plates improves the mid-height section axial mass velocity increment, I.e.non dimensionality, from 17.8% to 15.1% .slightly diverging the partition plates further improves it to11.0%.But further increase of diverging angle gives bigger increment, meaning worse approximation to twodimensional flow.Al so, the cascade characteristics with optimum diverging partition plates are compared with those tested without partition plates.