Abstract: Soot is a crucial radiative product in combustion processes, exerting a significant influence on energy efficiency and pollutant emissions. However, the complexity of the soot formation process has led most existing models to rely on complex chemical reaction mechanisms, resulting in high computational costs and limiting corresponding widespread adoption in engineering applications. To address this issue, a laminar smoke point model and a full-spectrum k-distribution radiation model were embedded using user-defined functions in ANSYS-Fluent software to efficiently simulate soot formation and radiation characteristics in ethylene laminar diffusion flames. The soot concentration fields and spectral radiative intensities under different blending ratios were measured by using a complementary metal oxide semiconductor (CMOS) camera and a Fourier-transform infrared spectrometer, so as to validate the effectiveness of the overall model. Results demonstrate that, through a single-step chemical reaction and an additional species transport equation, the proposed model can accurately capture the morphological characteristics of soot distribution within the flame. The radial average volume fraction distributions of soot at different heights exhibit good agreement with experimental data. Meanwhile, the simulated spectral radiative intensities at different heights match well with the measured values, validating the efficiency and accuracy of the overall model. This provides a reliable tool for engineering calculations of soot formation and radiation characteristics in flames.