In this study the penetration of spudcan foundation for "jack-up rig" type offshore oil platform into a uniform clayey seabed is investigated with three-dimensional finite element modeling (Abaqus 6.14) using Coupled Eulerian Lagrangian method that can handle large deformation problems. One of the goals of this study is to compare the penetration-bearing resistance behavior of spudcan obtained by numerical study with the method suggested in InSafeJIP design guideline. For the spudcan geometry and soil properties used in this study, based on the three dimensional finite element analyses, the required penetration depth for a target bearing capacity of spudcan is less than that required by analytical method in InSafeJIP guideline. The second goal of the study is to explore the effects of some geometrical and soil variables on spudcan bearing resistance-penetration behavior. The variables in this study are spudcan diameter (7.5 to 15 m), the surface roughness of spudcan (roughness coefficient of 0 to 1.0) and undrained shear strength of clay (20 to 80 kPa). Understanding the relations between the factors and penetration behavior may help in future studies on enhanced and economical design of spudcans.