Abstract: A fast ray tracing method based on ant colony algorithm is proposed to analyze the indoor propagation characteristics of millimeter-wave more efficiently. This method uses ant colony distribution calculation and heuristic search principle to find the dominant ray path of radio wave propagation, which replaces the total ray path analysis to reduce the algorithm complexity and improve execution efficiency. Compared with the measured data results, the result of the simulation analysis of three frequency channel characteristics of 28 GHz, 32 GHz and 38 GHz in typical indoor scene shows better consistency, and the prediction error is less than 0.8 dB. The computational efficiency is improved by 378.9% compared with the traditional ray tracing method. The above-mentioned results show that the proposed method can effectively reduce the computational complexity under the premise of ensuring the prediction accuracy, and has the value of engineering application.