The flow behavior of polyethylene oxide (PEO) aqueous solution with the mass fraction of 0.30% in a 4:1 contraction microchannel was studied by the experimental and numerical methods in this paper. With finite element analysis software Polyflow, the exponential Phan-Thien-Tanner (PTT) constitutive model was applied to simulate the flow behavior of the solution in 4:1 right angle contraction microchannel and 4:1 arc transition contraction microchannel at Weissenberg numbers of 5.9, 7.2, 8.1 and 9.8. The results show that the experimental results agree well with the numerical simulation results. It is proved that the PTT constitutive model can well predict the rheological behavior of PEO aqueous solution in 4:1 contraction microchannel. Furthermore, the influence of Weissenberg number and geometry of the channel on the microscale flow behavior were discussed. With the increase of Weissenberg number, the flow velocity, pressure and stress of PEO aqueous solution also increase, and the arc transition contraction port can effectively avoid vortex flow and improve the stability of extrusion flow field.