Abstract: CTIA (Cellular Telecommunications Industry Association) developed a test standard for wireless devices, which can provide effective reference for testing of wireless communication products such as mobile phone and so on. The most important content in the test standard is ripple measurement. It is benefits for export of wireless communication products after obtaining the accreditation of the CTIA OTA laboratory. The ripple performance of the OTA anechoic chamber is a very important parameter, which directly affects the uncertainty of the OTA test results. This paper analyzes the ripple measurement technology for anechoic chamber in assessment and validation of CTIA OTA, and systematically describes the measuring principle, measuring method, test equipment and solutions to problems encountered. This work has a positive effect on obtaining the validation of CTIA OTA laboratory.