Crucial　to　regional　integration　and　sustainability　of　urban　agglomeration,　coordination　between　urban　land　expansion　and　population　growth　caused　by　rapid　urbanization　has　drawn　increasing　attention.　Though　the　population-land　relationship　has　been　widely　explored,　few　studies　have　investigated　the　internal　mechanism　from　an　allometric　growth　perspective.　This　study　aims　to　reveal　spatiotemporal　evolution　and　influencing　factors　of　population-land　coordination　in　26　central　cities　of　Yangtze　River　Delta　(YRD)　from　1989　to　2018,　via　incorporating　the　coupling　coordination　model,　super-slack-based　measure　model　(Super-SBM),　and　spatial　Durbin　model　with　fixed　effects.　The　results　indicated　that:　1)　the　pace　of　land　expansion　significantly　exceeds　population　growth,　and　great　distinction　of　allometric　growth　within　regional　cities　is　observed;　2)　population　-land　interaction　is　still　located　in　the　low　coordination　stage,　and　its　productivity　efficiency　sees　a　slight　fall　with　fluctuation;　3)　urban　land　exploitation,　population　agglomeration　and　productivity　efficiency　have　significant　positive　effects　on　population-land　coordination.　Finally,　several　recommendations　are　proposed,　involving　targeted　urban　land　supply　for　different　cities,　trans-administrative　regional　land　and　industrial　planning.　This　study　provides　some　insights　into　the　sustainable　population-land　relationship.