We report the measurement of majority carrier concentration, depletion width, mobility, and resistivity in a thin-film based Cu2ZnSnSe4 (CZTSe) photovoltaic device. The carrier transport properties were measured using coordinated admittance spectroscopy and capacitance-voltage technique. The bias dependence of the modified dielectric relaxation in the absorber of the CZTSe solar cell was investigated to extract the mobility and resistivity. Hall measurement was also performed at room temperature for the verification of carrier concentration, resistivity, and mobility. The temperature dependent resistivity and mobility exhibit thermally activated behaviors characterized by a thermal activation energy approximate to 60 meV. The positive temperature dependence of the mobility indicates a carrier-transport impeding effect caused by the band-edge fluctuation in poly-crystalline CZTSe, whose magnitude is measurable by the aforementioned activation energy.