Abstract: Subsurface drip irrigation (SDI) with micro-nano bubble water (MNBW) is one of the most efficient irrigation modes of water-saving oxygenation. Biochar is one type of biomass resource with abundant porosity. Both of them can be expected to alleviate the hypoxia in the root zone of crops. This study aims to explore the effects of the micro-nano bubble water coupled with the biochar on soil aeration, as well as the yield and quality of crops. The research material was taken as the fruit cucumbers in southern red soil. A two-factor randomized block was also designed in the greenhouse. Three concentrations of dissolved oxygen were set in the micro-nano bubble water (O1, 4-5 mg/L; O2, 9-10 mg/L; and O3, 14-15 mg/L). Three amounts of biochar were also applied (B1, 20 t/hm²; B2, 40 t/hm²; and B3, 60 t/hm²). Additionally, a control group (CK) was established (O, 4-5 mg/L, dissolved oxygen in irrigation water under natural conditions; B, 0 t/hm², no biochar applied). An integrated system was employed as the water and fertilizer underground drip irrigation. A systematic investigation was carried out to explore the effects of the dissolved oxygen concentrations of micro-nano bubble water and biochar application amounts on the soil aeration, cucumber yield, and quality over two growing seasons (1^st and 2^nd crop). The results indicate that the dissolved oxygen concentration of micro-nano bubble water and biochar significantly enhanced the main indicators of soil aeration, yield, and quality (P<0.05). The yield of fruit cucumbers was positively correlated with the soil aeration porosity (P<0.05), soil redox potential (P<0.01), soil oxygen (P<0.01), and irrigation water use efficiency (P<0.01). There was a negative correlation with the soil bulk density (P<0.05). The porous properties of biochar increased the porosity of soil and aeration, thus enhancing the soil moisture and oxygen levels when mixed with the micro-nano bubble water. The bulk density of red soil was reduced correspondingly. The aeration of the red soil was improved for the high yield and quality of fruit cucumbers. In terms of yield, quality, and financial gains, O3B3 was the best treatment among them. The finding can also provide a feasible approach to improve the aeration of clayey red and yellow soils in southern China.