Abstract: Microwave anechoic chambers are enclosed spaces specifically designed for measurements in the microwave frequency range, used as experimental sites for antenna and target scattering characteristics measurements to simulate free space. Compared to outdoor test sites, these chambers offer advantages of all-weather operation and low reflection. However, due to the imperfect absorption of electromagnetic waves by internal materials in specific frequency bands, interfering reflected signals still exist in the test area. These signals enter from various directions and overlap with direct waves between transceiver antennas, forming spatial standing wave distributions over certain distances. The interference reflection index in the test area is characterized by the quiet zone reflectivity level. When using microwave anechoic chambers to measure parameters such as antenna radiation patterns, the reflectivity level at different angles should be evaluated. The free-space voltage standing wave ratio (VSWR) method is commonly employed to measure this reflectivity level. In the test area, the vector sum of direct and reflected signals forms spatial standing waves along specific paths. The data processing method for these standing waves determines the calculated reflectivity level of the quiet zone, with the selection of peak-to-peak values in actual test curves directly influencing measurement results. This article discusses in detail the collection and processing methods of reflection level data in microwave anechoic chambers, aiming to optimize on-site measurement and testing schemes. Additionally, this research provides valuable insights for the optimal design of quiet zone scanning frames, potentially enhancing the overall accuracy and reliability of microwave measurements in anechoic environments.