This is the first of a series of papers devoted to the topology of symplectic Calabi-Yau 4-manifolds endowed with certain symplectic finite group actions. We completely determined the fixed-point set structure of a finite cyclic action on a symplectic Calabi-Yau 4-manifold with b1 > 0. As an outcome of this fixed-point set analysis, the 4-manifold was shown to be a T 2 -bundle over T 2 in some circumstances, e.g., in the case where the group action is an involution which fixes a 2-dimensional surface in the 4-manifold. Our project on symplectic Calabi-Yau 4-manifolds is based on an analysis of existence and classification of disjoint embeddings of certain configurations of symplectic surfaces in a rational 4-manifold. This paper laid the ground work for such an analysis at the homological level. Some other results which are of independent interest, concerning the maximal number of disjointly embedded symplectic (−2)-spheres in a rational 4-manifold, were also obtained.