  To overcome the signal disturbance from the transmission process, recently, a
new type of protocol named round-robin differential-phase-shift(RRDPS) quantum
key distribution[Nature 509, 475(2014)] is proposed. It can estimate how much
information has leaked to eavesdropper without monitoring bit error rates. In
this paper, we compare the performance of RRDPS using different sources without
and with decoy-state method, such as weak coherent pulses(WCPs) and heralded
single photon source(HSPS). For practical implementations, we propose finite
decoy-state method for RRDPS, the performance of which is close to the infinite
one. Taking WCPs as an example, the three-intensity decoystate protocol can
distribute secret keys over a distance of 128 km when the length of pulses
packet is 32, which confirms the great practical interest of our method.
