Owing to their unique optical and electronic properties, two-dimensional (2D) materials have demonstrated broad promising applications in optoelectronic devices. Molybdenum disulfide (MoS₂), a representative 2D material, has shown remarkable advantages in the field of photodetection because of its atomic-level interfaces and thickness-dependent tunable band structure. However, after many years of extensive studies, MoS₂ devices have reached a bottleneck in terms of performance. To further improve the performance of MoS₂ devices, various methods, such as band engineering, ferroelectric polarization, and plasmon resonance, have been investigated. However, a thorough review of such studies has not been conducted. In this paper, we briefly summarize the latest theoretical and practical research into MoS₂ photodetectors. The principles, structure design, preparation, and optoelectronic characteristics of the new MoS₂ photodetectors based on the three aforementioned methods were reviewed. This comprehensive review can broaden the existing understanding of MoS₂ devices and provide important guidelines for future applications.