Quantum teleportation is considered as the most basic process of quantum communication. It is undoubtedly beneficial for the realization of quantum teleportation while transmitting the maximum number of quantum bits with the minimum number of quantum channel resources. An improved bidirectional quantum teleportation protocol based on a quantum channel of six-qubit cluster state is proposed. In this paper, the user Alice can transmit an unknown three-qubit entangled state to the user Bob, and at the same time, the user Bob can transmit an arbitrary single-qubit state to the user Alice by utilizing GHz-state measurement, bell-state measurement, single-qubit Von Neumann measurement, and unitary operations. Compared with other schemes in quantum resource consumption, necessary operation complexity including operation difficulty and intensity, classical resource consumption, quantum information bits transmitted, and intrinsic efficiency, our scheme has the remarkable advantages in transmitting more quantum information and possesses higher intrinsic efficiency.