In this paper, on the basis of the tunable electromagnetically induced transparent (EIT), a temperature sensing system composed of plasmonic side-coupled resonant cavity is proposed. Utilizing the finite difference Time domain (FDTD) method, we investigated that the central wavelength of the transmission window can be precisely regulated by changing the amount of liquid injected into the cavity. The temperature sensing performance of this system was investigated in conjunction with the sensitivity of surface plasmon polaritons (SPPs) to the dielectric properties of the surrounding environment. It is achieved that the resonance wavelengths for injected chloroform and alcohol are both linear with the change of ambient temperature, and the best temperature sensitivity corresponding to chloroform can reach 0.425 nm/℃, which is higher than that of alcohol. The results may provide theoretical guidance for the development of highly integrated optical switching, sensing, and slow light devices.