The transient nature of optical absorbance and the microwave cavity perturbation technique are used to measure the minority carrier lifetime in a polycrystalline thin film of Zn3P2 as well as to observe the spectral photoabsorbance. It has been observed that the transient decay curves consist of two components attributed to the surface carriers and the bulk carriers. The analysis of these spectral variation of carrier lifetime and spectral photoabsorbance indicate the possible band-band transitions in this material.