The　effect　of　＇space-time　compression＇　caused　by　＇space　flow＇　breaks　the　independent　allocation　of　resources　between　cities　and　drives　the　formation　of　regionally　integrated　development　pattern,　and　the　organizational　structure　and　operation　mechanism　of　the　urban　network　cannot　be　separated　from　the　inter-city　relationship.　Based　on　Baidu　migration　big　data　from　October　2021　to　September　2022,　this　paper　constructs　the　intercity　population　flow　network　for　366　cities　in　China.　At　the　node　level,　a　population　flow　surpassing　index　is　proposed　to　measure　urban　centrality　and　explore　the　spatial　clustering　characteristics　of　urban　centrality.　At　the　network　community　level,　the　monthly　intercity　population　flow　pattern　and　characteristics　of　366　cities　are　analyzed.　The　results　show　that:　(1)　The　population　flow　surpassing　index　considering　flow　direction　meets　the　actual　needs　of　intercity　population　mobility　evaluation　for　measuring　urban　centrality　and　can　effectively　characterize　the　centrality　of　cities　in　the　intercity　population　flow　network.　Using　Baidu　Migration　big　data　from　January　2023　to　April　2023　after　the　end　of　the　epidemic　for　comparison,　we　found　that　the　central　impact　on　national　central　city　is　small　due　to　the　prevention　and　control　of　COVID-19　transmission;　(2)　Cities　in　the　intercity　population　flow　network　exhibit　＇High-High　(HH)＇　and　＇Low-Low　(LL)＇　agglomeration　characteristics　according　to　their　centrality.　HH　clustering　areas　are　formed　in　the　eastern　coastal　and　central　regions,　while　LL　clustering　areas　are　mainly　located　at　the　edge　of　the　Qinghai　Tibet　Plateau,　the　edge　of　the　three　northeastern　provinces,　and　some　areas　in　Hainan　Island;　(3)　The　intercity　population　flow　pattern　shows　different　characteristics　in　different　months　due　to　the　influence　of　holidays,　COVID-19　transmission,　etc.,　generally　in　accordance　with　the　first　law　of　geography,　and　exhibits　provincial　differentiation　characteristics;　(4)　The　finding　of　urban　cohesive　subgroups　shows　that　the　intercity　population　flow　patterns　of　Chengdu-　Chongqing　Urban　Agglomeration,　Greater　Bay　Area,　Central　Plains　Urban　Agglomeration,　Guanzhong　Plain　Urban　Agglomeration,　Yangtze　River　Delta　Urban　Agglomeration,　and　other　urban　clusters　are　relatively　stable,　characterized　by　cross-provincial　population　flow　integration.　The　Shandong　Peninsula　Urban　Agglomeration　and　the　Beijing-　Tianjin-Hebei　Urban　Agglomeration　have　close　connection　in　intercity　population　flow　patterns,　characterized　by　cross-urban　cluster　intercity　population　flow.　The　intercity　population　flow　pattern　within　Zhejiang　Province　is　gradually　enhanced,　and　the　urban　clusters　in　middle　reaches　of　Yangtze　River　and　the　west　bank　of　the　Taiwan　Strait　haven’t　yet　formed　a　stable　population　flow　pattern　across　provincial　borders.　©　2024　Science　Press.　All　rights　reserved.