Abstract: In order to explore the effective ways for high-abundance carbon and chlorine isotopes production, a method to acquire high-abundance carbon-12 and chlorine-35 isotopes simultaneously was presented by gas centrifugation process using Freon-11 as processing gas. Carbon and chlorine isotopes were separated by single centrifugal experiment of domestic centrifuge. A proper mass spectrometric method was proposed to analyze the separation performance. Theoretical calculation on cascades for producing high-abundance carbon-12 and chlorine-35 isotopes was applied. The results showed that using a 24-stage square cascade, with the 3rd stage as feeding stage and reflux at both ends, carbon-12 and chlorine-35 isotopes of an abundance of above 99% could be acquired simultaneously. The experimental study and theoretical calculation provided evidence for the production of high-abundance carbon-12 and chlorine-35 isotopes. In theory, the method could also be applied to the production of high-abundance carbon-13 and chlorine-37 isotopes.