For the deficiencies of the existing polarization measurement system in the observation of Omnimax polarization mode, we build a full-sky imaging polarimeter system with full polarization measuring ability. The system is composed of fisheye lens, linear polarizer, quarter-wave retarder, macro lens, and CMOS camera, and presents some impressive measuring capabilities of nearly 180-degree field of view, full-polarization measurements and portable. We firstly introduce the system structure, working principle and optical design and the corresponding calibration method to obtain the system Muller matrix. System calibration makes the linear and circular polarization measurement errors less than 3% and 10%, respectively. Then, we obtain the full-sky skylight polarization patterns at the zenith at 488 nm band at the sunrise in the clear sky experiments. The experimental results are consistent with the theoretical value, which verifies the validity of the system in the Omnimax polarization characteristics observed.