Electromagnetic pollution is becoming a serious concern. Electromagnetic wave absorbers with light weight, high efficiency and broadband are desirable for electromagnetic protection. Recently, 1T/2H hybrid molybdenum disulfide nanosheets attracted great attention due to the enhanced microwave attenuation driven from fabrication of 1T/2H metal-semiconductor heterojunctions. However, the easy and controllable 1T/2H phase tailoring remains a challenge because of the difficulty in accurately controlling the two-phase ratio and the complicated process. In this study, a facile hydrothermal process is proposed to acquire the 1T/2H MoS₂ nanosheets with different 1T contents. The high-resolution TEM images reveal the MoS₂ nanosheets are composed of 1T/2H nano-heterojunctions with the 1T and 2H nanodomains arranged alternatively. Without compositing with conductive matters, the MoS₂ nanosheets exhibit excellent microwave absorption performance with a maximum reflection loss of −27 dB and an effective absorption bandwidth of ∼4.16 GHz (at 2.3 mm thickness). It benefits from the increased conductivity of the MoS₂ nanosheets, abundant 1T/2H phase boundaries and lattice defects, and improved impedance matching induced by the embedding of the 1T phase in the 2H matrix. This work demonstrates the feasibility of the proposed facile hydrothermal process in achieving 1T/2H phase regulation, providing an effective method to tailor the properties of MoS₂ nanosheets for various applications.