Polarization is a fundamental physical dimension of electromagnetic waves. However, experimental determination of polarization states of light is inherently challenging and inconvenient due to the loss of phase information in conventional optical characterization. In particular, the Stokes parameters are a critical indicator to fully describe arbitrary polarization state, which, however, require multiple intensity measurements in three orthogonal polarization bases. Here, we design and experimentally demonstrate a multi-tasking geometric phase element array to unveil all Stokes parameters in one shot. Such a method is convenient, broad-band, real-time with compact size to accurately characterize the complex polarization states of coherent light, which may find visionary applications in structured light microscopy, polarizable quantum computation, and communication, etc.