Two-dimensional molybdenum disulfide (MoS₂) has emerged as a promising material for optoelectronic applications because of its superior electrical and optical properties. However, the difficulty in synthesizing large-scale MoS₂ films has been recognized as a bottleneck in uniform and reproducible device fabrication and performance. Here, we proposed a radio-frequency magnetron sputter system, and post-treatments of electron beam irradiation and sulfurization to obtain large-scale continuous and high-quality multilayer MoS₂ films. Large-area uniformity was confirmed by no deviation of electrical performance in fabricated MoS₂ thin-film transistors (TFTs) with an average on/off ratio of 10³ and a transconductance of 0.67 nS. Especially, the photoresponsivity of our MoS₂ TFT reached 3.7 A W^–1, which is a dramatic improvement over that of a previously reported multilayer MoS₂ TFT (0.1 A W^–1) because of the photogating effect induced by the formation of trap states in the band gap. Finally, we organized a 4 × 4 MoS₂ phototransistor array with high photosensitivity, linearity, and uniformity for light detection, which demonstrates the great potential of 2D MoS₂ for future-oriented optoelectronic devices.