An analytical approach to the impact of polarization aberration on lithographic imaging is proposed. The linear relationship between image placement error (IPE) of alternating phase-shifting mask (Alt-PSM) and odd aberration items of polarization aberrations, as well as that between best focus shift (BFS) of Alt-PSM and even aberration items of polarization aberrations are established by analytical equations, respectively. The validity of the linear relationships is demonstrated by numerical results. The differences and connections between scalar aberration and polarization aberration are briefly discussed based on these linear relationships.