We consider a single-level quantum dot (QD) and a topological superconducting wire hosting Majorana bound states at its ends. By the equation of motion method, we give the analytical Green's function of the QD in the noninteracting and the infinite interacting case. We study the effects of QD energy level and the spin polarization on the density of states (DOS) and linear conductance of the system. In the noninteracting case, the DOS resonance shifts with the change of energy level and it shows bimodal structure at large spin polarization strength. In the infinite interacting case, the up-spin linear conductance first increases and then decreases with the increase of spin polarization strength, but the down-spin is stable. However, the DOS shows a splitting phenomenon in the large energy level with the increase of spin polarization strength. This provides an interesting way to explore the physical properties of such spin dependent effect in the hybrid Majorana QD systems.