Low voltage DC distribution networks have flexible access to distributed generations, energy storage devices and DC loads, which have been widely developed. T-source circuit breaker can solve the problems of DC distribution network protection. Compared with Z-source circuit breakers, T-source circuit breaker has the advantages of common ground, zero reflected current and low-pass filtering. However, the traditional bidirectional Z-source and T-source circuit breakers have multiple power semiconductor devices in the steady-state path, which leads to low efficiency of circuit breakers. Therefore, this paper proposes a novel efficient bidirectional T-source circuit breaker, which has only one SCR in the steady-state path. Compared with traditional bidirectional Z-source and T-source circuit breakers, the on-state power loss of the proposed circuit breaker can reduce more than 50%. Finally, the capabilities of the proposed circuit breaker are verified by simulations and experiments.