The residence time of particles in a circulating fluidized‐bed (CFB) reactor is the essential parameter for design and performance of a CFB system. In this work, a noninvasive measurement method of positing tracer particles in a full‐loop CFB system is proposed. Based on the radio frequency identification technology, more than 400 tracer particles with individual code were made and moved freely in the CFB full loop system. With detecting the tracer particles' trajectory by high‐frequency readers located outside of the system, the effects of operating parameters including fluidization number and solid inventory on the movement and residence time of the tracer particles in the CFB system were investigated. The particle residence time is distributed in a certain range, influenced by superficial gas velocity and solid inventory.