In order to analyze the character of light and system, the polarization states of transmitted light through the liquid crystal spectropolarimetric system are investigated in the different modulation cases. After the Mueller matrix of system is obtained based Stokes vector and Mueller matrix theory, the distribution of the polarization states of incident light is drawn down in a ball with varied modulations of different rotatory angle, different areas and different phase delay. The reached conclusion is that the incident light is changed from completely polarized light to partially polarized light through system, which is clustered together around 45° in x-y plane and turned into linearly polarized light. Gathering together is mainly caused by tunable filter and varied modulation types lead to different gathering positions around 45°. By investigating the polarization states of transmitted light through the liquid crystal spectropolarimetric system, the change rules of polarization states are obtained which can lay the foundation for system optimization and light properties analyzing.