Measurement-device-independent quantum key distribution (MDI-QKD) protects the receiver from attacks against the measurement devices. Decoy state method allows the unconditionally secure quantum key generation with lasers. However, two independent lasers for MDI-QKD have to send indistinguishable photons. In this report, we will discuss the effects of the two-photon distinguishability in terms of the visibility of the HOM-dip of two photons on the final key rate by simulation. The acceptable visibility range is estimated.