In response to the insufficient synergy between water and phosphorus and the low utilization efficiency of phosphorus fertilizers in muskmelon production，this study investigated the effects of water and phosphorus coupling under drip irrigation on the photosynthetic characteristics and yield of thick-skinned muskmelon in a 2-year greenhouse field trial.The study aimed to explore the appropriate ratio of water and phosphorus coupling，providing a theoretical basis for the efficient utilization of water and fertilizer in muskmelon production under drip irrigation.The muskmelon variety ‘Zao Xiangmi’ was used as the experimental material.In 2020，the treatments consisted of two soil matric potentials，W1(-20 kPa) and W2(-40 kPa)，and five phosphorus application rates，P0(0 kg/hm² P2O5)，P1(21.15 kg/hm² P2O5)，P2(58.65 kg/hm² P2O5)，P3(96.15 kg/hm² P2O5)，and P4(133.65 kg/hm² P2O5).In 2021，the treatments consisted of three soil matric potentials，W1(-20 kPa)，W2(-30 kPa)，and W3(-40 kPa)，and four phosphorus application rates，P0(0 kg/hm² P2O5)，P1(75 kg/hm² P2O5)，P2(150 kg/hm² P2O5)，and P3(225 kg/hm² P2O5).The results showed that under the same soil matric potential，the main vine length，stem diameter，aboveground dry matter accumulation，yield and phosphorus fertilizer partial productivity of thick-skinned muskmelons increased initially and then decreased with the increase in phosphorus application rates.Under the same phosphorus application rate，the plants treated with a soil matric potential of -20 kPa had significantly higher main vine length，stem diameter，aboveground dry matter accumulation，yield，and phosphorus fertilizer partial productivity compared to those treated with -30 kPa and -40 kPa.By appropriately increasing the soil matric potential and phosphorus application rate，the photosynthetic efficiency and water use efficiency were significantly improved，along with increased dry matter accumulation，leading to an increase in muskmelon yield.In 2020，the phosphorus fertilizer partial productivity was the highest in the W1P1 treatment，while the yield was the highest in the W1P2 treatment，with increases of 21.02% and 16.4% compared to the no phosphorus application treatment，respectively.In 2021，both the phosphorus fertilizer partial productivity and yield were the highest in the W1P1 treatment，with a 20.30% increase in yield compared to the no phosphorus application treatment.Considering all factors，the suitable drip irrigation water and phosphorus management model for thick-skinned muskmelons in local greenhouses should be a soil matric potential of -20 kPa and a phosphorus application rate of P2O5 58.65 or 75 kg/hm².