The microscopic view of the damage accumulation process (initiation of micro-crack) during cyclic loading can be summarized as follows : (1) appearance of local plastic strain, (2) localization of these local plastic strains and then formation of non-reversible slip, (3) formation of persistent slip band (PSBs), (4) accumulation of non-reversible slip within PSBs, (5) formation of intrusion within PSBs, (6) growth of intrusion and formation of micro-crack. Therefore, it is possible to consider that the amount of accumulated shear strain and non-reversible slip can be used as the parameters which represent a process of crack initiation. If we can analyze the relationship between the macroscopic loading conditions and such microscopic parameters by crystalline FEM analysis, it can be considered to improve the prediction method of crack initiation life. In the previous papers, the authors has developed a crystalline FEM code which can analyze the cyclic plastic deformation behavior of f. c. c. crystals both on the occurrence of material unstability and under variable amplitude loading conditions. Using the FEM code, the non-uniform deformation of f. c. c. cubic single crystal under various kinds of variable amplitude cyclic loading conditions are calculated. As a result, the acceleration of plastic strain localization and the generation of non-reversible slip are derived. By investigating the relationship between the loading conditions and the amount of accumulated shear strain and non-reversible slip, the non-linearity of fatigue damage accumulation process are discussed.