Thermoelectric materials can directly convert thermal energy into electrical energy by using the directional transfer of carriers in solid, and have broad application prospects in deep space exploration and industrial waste heat recovery power generation. The physical parameters that affect the thermoelectric transport behavior are coupled with each other, which makes it difficult to improve the thermoelectric figure of merit. SnTe is a kind of environment-friendly mid-temperature thermoelectric materials, which has received extensive attention in recent years. In view of the disadvantages of SnTe such as high concentration of intrinsic cation vacancy, large offset between the two valence bands and high lattice thermal conductivity, the main methods for decoupling thermoelectric parameters and improving thermoelectric performance of SnTe in the past ten years are reviewed, including carrier concentration optimization, energy band structure adjustment, crystal defect design and construction, etc. The mechanism and physical nature of each optimization method are discussed. It is pointed out that heavy doping in SnTe will lead to the decline of mechanical properties while improving thermoelectric performance, and the trade-off between thermoelectric and mechanical properties in practical applications is emphasized. Moreover, the major challenges of SnTe from materials to devices are prospected.