A search for heavy resonance decaying into a photon and a Higgs boson is performed, where the Higgs boson continually decaying into a pair of b-quarks. Data was collected from 2015 to 2018 using the ATLAS detector at the LHC at the center-of-mass energy of √s= 13 TeV with an integrated luminosity of 139 fb−1. To improve the sensitivity of this analysis, a novel H→bb tagger method, Center-of-Mass sub-jet b-tagging algorithm, is implemented to identify the two b-quarks in a single Large-R jet. There is no obvious deviation from the Standard Model prediction. Upper limit is set usingCLsstrategy at 95% confidence level. Compared with previous ATLAS and CMSresult, on top of the statistic gain, more than 30% improvement is observed in the expected upper limit.