The concept of solar-hybrid coal-fired power plant is to use concentrated solar thermal energy to replace the extracted steam in regenerative Rankine power cycle. In this way, solar heat is capable of assisting coal-fired power plants to increase generating capacity with the same consumption of fuel, or remaining the same generating capacity but reducing its green house gas emissions within the same range. The advantages of a solar-hybrid coal-fired power plant in terms of design have been discussed by many researchers. However, off-design thermodynamic performances have not been well discussed yet. In this study, a typical 330 MW coal-fired power plant in Sinkiang of China is selected as the case study to denote the off-design thermodynamic performance. Influences of three main factors including solar radiation, incident angle and turbine load, on key parameters such as solar-to-electricity efficiency and net solar power ratio are discussed. Annual thermodynamic performances are discussed. The results obtained in this study could provide some guidance for the design and construction of solar-hybrid coal-fired power plant.