The reflected radiation generated by the interreflection between the inner surfaces of cavity-like objects is not easy to measure directly and leads to temperature measurement errors. In this article, the effect of reflected radiation on temperature measurement was described based on effective emissivity modeling, which does not require direct determination of reflected radiation. Based on different modeling principles, we proposed two methods to estimate the actual temperature of the inner surface by effective emissivity models and pyrometer measurements. Simulation calculation was designed to test the feasibility of both methods. The experiment was conducted to verify the proposed methods. Compared with the conventional method, the proposed methods achieved an improved performance on inner surface temperature measurement, demonstrating a decline in the average error from 1.17% to 0.31% and 0.27%, respectively.