Abstract: Comparisons in developments and applications between Radioimmunoassay (RIA) and chemiluminescence immunoassay (CLIA) in medical diagnosis were descriped. According to my job and the applications of RIA and CLIA in China, the developments, detection levels and application prospects of the two methods were reviewed in China. Both RIA and CLIA were high sensitive, and there was a good relativity between each other. RIA was variety limitless, widely testing fields and high coverage, which can be used in clinical diagnosis and lab research. Coupled with the lower fees, RIA was still one of the most important choices in the future. The operations in CLIA tests were simple, fast and automated. No nuclear pollution was a big advantage of CLIA to RIA. CLIA was becoming more and more competitive. Based on the policy and developments of RIA technologies, the market rate of RIA would grow rapidly in future.