Abstract: Shadowing effects is one of the main consideration factors in designing complex system with multiple antennas. There will be 373 sets of antennas in Mingantu Station, after completing the construction of the program Meridian II equipment of National Major Science and Technology Infrastructure. Limited by test site, model complexity and computation, shadowing effect is usually hard to measure and to predict especially for electrically large-size structures. The observed solar radio data on S/C/X bands between 2017 and 2020 by MST (Mingantu Solar Radio Telescope), present the shadowing effect with the 20 m antenna and remote hills as obstacles. The observed data with shadowing effect can be divided into antenna area, atmosphere area and hill area with different shadowing characteristics. Based on the prediction method of single knife-edge diffraction loss recommended by ITU-R P.526-15, a model of 20 m antenna reflector is built, the shadowing effects on S/C/X-bands are simulated, and the results show good agreement with those of observation. From simulation and observing results, shadowing effects are related with wavelength, obstacle character, distance and angle among obstacle, source and receiving antenna, the receiving antenna's beam, and dynamic range of receiving system, etc.