The Monte Carlo method is the basis of calculating global illumination. Many Monte Carlo-based global illumination algorithms have been proposed. However, most of them have some limitations in terms of rendering time. Based on the Monte Carlo method, a new global illumination algorithm was proposed, combining the Metropolis ray tracing algorithm with an integrated filter. The algorithm is composed of two parts. In the first part, multiple sets of filters with different scales were used to smooth the image; in the second part, filtered images were combined into the final result. Relative Mean Squared Error (RMSE) was used as a basis for the selection of filtering scale, and an appropriate filter was adaptively selected for each pixel during the process of sampling and reconstruction, aiming to reduce the errors to a minimum degree and gain better reconstruction results. Experimental results show that the proposed method outperforms many traditional Metropolis algorithms in terms of both efficiency and image quality.