When a lithium-ion battery is thermally out of control, the internal heat is mainly coming from the mutual reaction of the internal components of the battery. It is well known that the breakdown and combustion of carbonate solvents inside lithium-ion batteries contribute a large part of the heat when thermal runaway occurs. Therefore, it is necessary to analyze the combustion characteristics of several common carbonate solvents. The cone calorimeter was used to test the combustion of four common carbonate solvents and their mixed solution under different thermal radiation conditions. The obtained heat release rate (HRR), mass loss rate (MLR) and total heat release (THR) were used to analyze its combustion characteristics. Meanwhile, the HRR of different carbonate solvent configurations was explored and compared by oxygen consumption calorimetry (OC) and thermochemical theory (TC). The results show that the HRR curve obtained by the TC method and the OC method basically coincide, which confirms the reliability of the OC method to measure the HRR of solvent combustion. The linear carbonates usually burn at an early stage in the combustion process because the evaporation rates of linear carbonates are higher than those of cyclic carbonates. The peak HRR of the solution combustion has a significant drop when the sample contains EC, whether it is under the premise of thermal radiation or without thermal radiation. The external thermal radiation is proved to have a great increasing influence on the peak HRR per unit area and MLR. These tests can be the reference of more detailed analysis of electrolyte reaction during lithium-ion battery fire, and provide a theoretical basis for preventing and restraining the thermal runaway.