Designing single-crystal superalloy blades to thin wall structures produces the secondary orientation which is the perpendicularity orientation of the wall surface, becoming a newly-concerned crucial factor of performance. Here, we have studied the influence of 110 and 112 secondary orientations on 1100 °C/137 MPa creep properties of 111-orientated single-crystal superalloys. The plastic deformation accumulation and the plastic limit during creep vary with secondary orientations. Our results give microstructural evidence of the change in the slip systems operation and micro-pore growth, and correlate the possible stress state in the thin wall to plastic deformation mechanism, and finally to properties, which can explain such influence. The results show that the activation of slip systems with different secondary orientations is different due to the different shear stress, and this difference of slip systems causes the difference of plastic deformation ability and pore growth and finally affects the creep performance.