An Al-3.0wt% Cu single crystal containing the single variant of GP zones was produced by using the stress-aging method to examine the effect of GP zone orientation on yield stress. There are two geometric conditions of intersecting process between dislocation and GP zone variants. One is that dislocation intersects parallel to zone plate (Type A), another is dislocation intersects by 60 degree (Type B). The yield shear stress of the specimen containing type-A GP zone was about 80 MPa and that of type-B was about 50 MPa. At R.T., the yield shear stress of type A and B specimens were about 50 and 45 MPa, respectively. The difference of the yield stress between type A and B specimen was evident at low temperature. The temperature dependence of yield stress was higher in type A than type B. From the results of temperature dependence of yield stress and strain-rate sensitivity, these geometric effects were explained by short-range interaction between moving dislocation and misfit strain.