Abstract Magnetic transport properties in Co2MnSn/IrMn/Pt trilayer structures have been investigated. Spin Hall magnetoresistance (SMR) enhancement in the trilayer structures has been observed, under the premise of exclusion current shunting effect. The experimental analysis indicates that the SMR enhancement may be closely related to the spin current enhancement reflected from the Co2MnSn/IrMn interface. Anomalous Hall resistance (AHR) study shows that its variation is quite similar to the SMR, suggesting that the SMR enhancement may also be closely related to spin-orbit coupled (SOC) scattering at the interface due to the coupling between IrMn and Co2MnSn layer. Temperature influences the SMR significantly in the trilayer structures at low IrMn thicknesses, which the IrMn has more ferromagnetic or ferrimagnetic orders than antiferromagnetic order. It indicates that the physical mechanism of the influencing of temperature on SMR of FM/AFI(AFM)/Pt trilayer structures need to be further investigated. The SMR changes its sign from positive to negative at temperatures lower than 50 K, revealing that spin-flop coupling between IrMn and Co2MnSn could happen at the interface.