Internal quantum efficiency (IQE) is a key parameter determining solar cell power conversion efficiency. While reported IQEs of metal-halide perovskite solar cells are often close to one, the contributions of photoluminescence reabsorption (PLr) and surface recombination (SR) to IQE has not been elucidated. In this work, both effects are examined by photoluminescence spectroscopies and time-resolved terahertz spectroscopy (TRTS). Then PLr rate and SR velocity are extracted from TRTS kinetics by diffusion theory. At last a model is proposed to calculate the carrier-collection probability and discuss contributions of PLr and SR on the IQE.