The nonradiative recombination presented at the quasi‐2D (Q‐2D) Ruddlesden–Popper perovskite surface/interface limits the overall performance of perovskite photoelectric devices. Here, a dual‐sided field effect passivation (FEP) strategy to reduce nonradiative recombination is reported. By inserting high/low work function dielectric layers between perovskite layer and hole/electron transport layers, the trap state density of perovskite layer is effectively reduced, resulting in a longer carrier lifetime. Besides, the carrier dynamics and the synergistic mechanism of chemical passivation (CP) and FEP are clarified in detail. The interfacial polarization caused by the work function difference between different layers prevents Shockley–Read–Hall (SRH) recombination loss of photogenerated electrons/holes and improves interfacial charge transport. Benefiting from it, the passivated photodetector performance has been improved effectively, achieving a dark current of 9.62 × 10−11 A, a linear dynamic range (LDR) width of 171.4 dB, and an ultra‐fast response time low to 430 ns, which are currently the highest reported detection indicators in the Q‐2D perovskite photodetectors. In addition, the dual‐sided field effect passivated intercalation inhibits perovskite decomposition and greatly improves the environmental stability. In future, exploring the synergistic effect of FEP and CP materials for perovskite films is one of the development directions for studying efficient and stable perovskite photoelectric devices.