Although the hot-casting (HC) method can obtain efficient quasi-2D perovskite solar cells, this method cannot effectively control the uniformity of the thin film, and the high preheating substrate temperature will also form low n perovskite phases ( n = 2) at the interface, which is not conducive to the transport of carriers. Semitransparent solar cells have great application prospects in building-integrated photovoltaic and tandem devices. Herein, a non-preheating (NP) film-casting method is proposed to realize a highly uniform and phase controllable quasi-2D perovskite film (BA 2 MA 3 Pb 4 I 13 , BA + :C 4 H 11 NH 3 + , MA + :CH 3 NH 3 + ). As a result, the NP-processed film gets the highest light utilization efficiency (LUE = 4.01%) for semitransparent quasi-2D perovskite solar cells (ST-Quasi-2D-PSCs) with power conversion efficiency (PCE) of 9.60%, average visible transmittance (AVT) of 41.73%, good bifaciality factor, high LUE in low light intensity and good stability.