This paper investigates the properties of silicon cells (SI) and perovskite solar cells (PSC) under bias condition by using impedance spectroscopy. The parallel resistances Rp of SI and PSC are found to decrease with increasing bias, but the capacitance Cp shows the opposite trend. Comparing Rp with Cp, bias has a greater impact on the Cp of both cells. However, the bias has little effect on the series resistance Rs of both cells. Compared with SI cell, the bias is seen to be a greater impact on the Rp and a smaller impact on Cp of PSC. The carrier lifetime τn in SI and PSC first increases and then decreases with bias, and the carrier diffusion length Ld increases almost linearly with bias. Compared to SI cell, the bias has a greater impact on PSC’s Ld.