Shear key connection is a very important part of the precast segmental bridge.The function of shear key in the connection of precast segmental bridge are to connect the precast segments of concrete become a complete structure of bridge and to distribute shear force from one segment to another segment. This study discusses about the shear key connection with male-female shear key from ferro cast ductile material. This study implemented by numerical simulation using ANSYS program with non linear analysis and applying two type of model, there are type 1 which using isotropic elasticity data and type 2 using multilinear isotropic hardening data. The purpose of this study is to get load of potential cracking in concrete and load of potential yielding in ferro cast ductile shear key by applying some variation of parameters. The variation of parameters were used to get shear key connection which has the maximum strength. The results of this study show that load of potential cracking in concrete will be greater if the grade of concrete and ferro cast ductile, prestressing force, diameter and number of shear key are increased. Variation of that parameters have the same effect to load of potential yielding in ferro cast ductile shear key, but load of potential yielding will be reduced if prestressing force are increased.