To investigate the effects of ridge-furrow planting system and planting density on photosynthetic characteristics and yield in a double-cropping rice system, a field experiment was conducted using the early-season cultivar ‘Zhuliangyou 819’and the late-season cultivar‘Taiyou 390’. A randomized block experimental design was employed with six treatments: CP(conventional density, flat cropping), ZP(density increased by 20%, flat cropping), C1 (conventional density, 1-m ridge width), Z1(density increased by 20%, 1-m ridge width), C2(conventional density, 2-m ridge width), and Z2(density increased by 20%, 2-m ridge width). Photosynthetic characteristics, leaf area index and yield were compared and analyzed across all treatments. The results showed that treatment Z1 maintained significantly higher relative chlorophyll content(SPAD value) than those of other treatments across all growth stages in both early and late rice. Increased planting density and ridge-furrow planting system independently contributed to a higher leaf area index. The early rice yield showed a significant positive correlation with the intercellular CO2 concentration(Ci) and transpiration rate(Tr) of the second-top leaf during the booting stage, as well as with the net photosynthetic rate(Pn), Ci, and stomatal conductance(Gs) of the flag leaf during the milky stage, while it exhibited a highly significant positive correlation with Tr during the milky stage. The late rice yield was significantly positively correlated with the Pn of the flag leaf at the heading stage and with the Pn and Ci of the flag leaf during the milky stage, while demonstrating a highly significant positive correlation with Tr during the milky stage. Compared to CP treatment, Z1 treatment increased SPAD value, Pn, Ci, Gs, Tr and leaf area index. Z1 treatment was beneficial to increase the effective panicle number and seed setting rate, thereby increasing rice yield. Compared to CP treatment, the yield of early rice increased by 14.67% and the yield of late rice increased by 11.92%. Comprehensive analysis showed that, for ridge-furrow planting, implementing a 1-m ridge width coupled with a 20% density increase could effectively improve the photosynthetic characteristics of rice and rice yield.