The clocking effect of a double stage compressor with positive bowed stator in different axial gaps between rotor and stator rows was investigated in this paper.The traverse flow field was measured in detail at the second stators outlet.The experimental results show that clocking effect changes little while the axial gap reduces.The diffusion ability intensifies while the input torque increases.The efficiency increases firstly and then decreases.It means that there is an optimal axial gap.At the same time

the surge margin decreases while the axial gap reduces.