Abstract: The aerodynamic interference between tandem square cylinders is strongly influenced by their geometric shape. The change of corner shape of square cylinders will lead to the change of flow field， which will affect the aerodynamic performance of square cylinders. The influence and mechanism of wind load interference effect of tandem square cylinders need to be further stud? ied.In this paper， the large eddy simulation method is used to investigate the impact and mechanism of corner cutting measures on the wind load of tandem square cylinders with subcritical spacing ratio and supercritical spacing ratio under two typical spacing ra? tios. The upstream and downstream cylinders are considered with or without corner cutting （the corner cutting rate is 10%）. The wind pressure coefficient of standard tandem square cylinders is compared with the wind tunnel test results in literature to verify the effectiveness of the simulation method and parameter setting. effects of different corner cutting measures on the aerodynamic perfor? mance of tandem square cylinders under two typical spacing ratios are compared and analyzed from the perspectives of aerodynamic coefficient statistics and auto-spectrum， average and fluctuating wind pressure coefficient distribution. The mechanism analysis is carried out from the perspective of time-average and transient flow field.The results show that under the two typical spacing ratios， the corner cutting measures at different positions will affect the flow separation around the square cylinder， resulting in the change of flow pattern. The average and fluctuating wind loads of the square cylinder can be reduced more effectively by the corner cutting measures at both upstream and downstream square cylinders.Under the subcritical spacing， the shielding effect is significant， and the corner cutting measures change the separation and reattachment position of the separation vortex， and reduce the lift and drag of the downstream square cylinder significantly.