Mid-wavelength infrared （MWIR） imaging technology plays a crucial role in aerospace， medical diagnostics， and autonomous driving. Van der Waals material black phosphorus （BP） exhibits exceptionally high carrier mobility and an ideal direct bandgap， making it a proven candidate for high-performance room-temperature MWIR sensing. However， the stringent growth conditions and anisotropic growth characteristics restrict the development of BP optoelectronic devices to small-scale laboratory demonstrations. Therefore， there is an urgent need to develop large-scale， uniform， and high-performance BP photodetector arrays. This study employed a room temperature preparation technique to deposit a large-area， uniform， low-oxidation BP ink film onto thin-film transistors， resulting in the development of a 64 × 64 high-performance MWIR snapshot photodetector array. The room temperature ink preparation process effectively prevents the oxidation of BP during fabrication， achieving a loss ratio as low as 1.12%. Additionally， a gradient centrifugation strategy enhanced the particle size and thickness concentration of the BP ink film， thereby facilitating the transport of charge carriers. The BP ink film array demonstrated a high photoresponsivity of 4.52 mA/W in the MWIR range， with pixel light response non-uniformity as low as 10.1%. This study presents a new approach for advancing large-scale MWIR imaging technology.