Host receptor recognition is a determinant for virus infection. During the time of this letter preparation, three works have just been published to explore the receptor usage of 2019-nCoV. A work by Zheng-Li Shi et al. has shown that angiotensin-converting enzyme 2 (ACE2), the receptor for severe acute respiratory syndrome coronavirus (SARS-CoV),3 from human, Rhinolophus sinicus bat, civet, swine but not mouse mediate 2019-nCoV infection in vitro, while the detailed mechanisms are not yet determined.4 The other two works have reported or predicted human ACE2 usage of 2019-nCoV in a similar way to SARS-CoV mainly based on the coronavirus spike (S) glycoproteins.5 , 6 Considering the fact that the S proteins mutate and gain capability to recognize host receptors among species,7 , 8 there is still a lack of analyses on receptor usage of 2019-nCoV from the receptor perspective, which does not evolve as quickly as viruses.