Solar cells using perovskite materials as absorption layers have attracted widespread attention due to their low cost and low loss. The working mechanism of perovskite solar cells is the generation and transmission of photo generated carriers. However, the internal defects and the defects at the interface of the material would promote carrier recombination, thus reducing the efficiency of the battery. In this work, daminozide (DA) was introduced as an interlayer and additive into perovskite solar cells, greatly passivating defects and significantly improving battery efficiency. The carrier relaxation dynamics was studied by ultrafast transient absorption spectrum. It is confirmed that the introduction of DA can significantly passivate defects in perovskite films, and led to excellent photovoltaic performance. The study provides theoretical guidance for the preparation of high-performance perovskite solar cells.