In order to improve the efficiency of key distribution, a quantum key distribution protocol based on W state and Bell state entanglement was proposed via quantum dense coding. In the scheme, the sender Alice codes the key successfully via local unitary operations, and the receiver Bob obtains the key with jointing measurement. All states can be used to transmit messages except those choosen for checking eavesdroppers, 5 bits deterministic key were distributed by 5 particles. Security analysis result by using information theory shows that the scheme is secure, any eavesdroppers can be found in time.