The principle of sensing of carbon dioxide using IR radiation is introduced and a novel double-beam optical structure is presented in the paper. Based on the good abilities of RBF network such as nonlinear mapping, learning and generalizing, the mathematic model of IR carbon dioxide sensor is established. A dynamic compensation filter is designed to improve the dynamic characteristic of IR carbon dioxide sensor. A novel IR carbon dioxide sensor with high performance is made. The experimental results show that the above key techniques prompt the accuracy, real-time and reliability of IR carbon dioxide sensor efficiently.