This　study　analysed　the　temporal　and　spatial　changes　in　the　water　yield　coefficient　(WYC),　which　represents　the　ratio　of　the　gross　amount　of　water　resources　to　precipitation.　Factors　such　as　precipitation,　rainstorm　days,　rainless　days,　vegetation　cover　change,　and　land　use/cover　change　were　considered　to　determine　the　causes　of　these　changes.　The　results　led　to　the　following　conclusions:　(1)　The　average　annual　WYC　of　the　Huang-Huai-Hai　River　Basin　is　between　0.03　and　0.58,　with　an　average　value　of　0.17,　which　is　smaller　than　the　national　average　WYC　of　0.4.　(2)　Temporally,　the　WYC　varied　slightly,　with　the　western　part　showing　a　negative　trend　and　the　eastern　part　showing　a　positive　trend.　The　WYC　is　positively　correlated　with　precipitation,　rainstorm　days,　and　the　normalized　difference　vegetation　index　(NDVI)　and　negatively　correlated　with　rainless　days.　However,　a　slower　change　in　NDVI　produced　a　faster　change　in　WYC.　In　areas　with　land　use　types　exhibiting　a　large　evapotranspiration　decrease,　the　rate　of　change　in　the　WYC　increased.　(3)　Spatially,　the　distribution　is　fairly　regular,　exhibiting　a　gradual　increase　from　the　northern　part　of　the　Yellow　River　Basin　(WYC　＜　0.1)　to　the　surrounding　areas.　When　the　WYC　is　correlated　with　precipitation,　rainstorm　days,　rainless　days,　and　NDVI,　the　R-2　values　of　the　linear　fitting　results　are　0.98,　0.91,　0.96,　and　0.73,　respectively.　The　WYC　is　positively　correlated　with　precipitation,　rainstorm　days,　and　vegetation　coverage　and　negatively　correlated　with　rainless　days,　but　the　correlation　coefficient　is　greatly　influenced　by　the　precipitation　characteristics　and　land　use　types.　In　areas　featuring　high　proportions　of　land　use　types　associated　with　high　evapotranspiration,　the　average　WYC　is　low.