Cassava variety Nanzhi 199 (sweet cassava variety, with erect, compact plant shape and generally unbranched at the top) and chili pepper variety Xiangyan 55 (medium maturity small cowpea variety, with good growth and strong adaptability) were used to study the effects of cassava-pepper intercropping pattern on cassava growth, photosynthetic performance, soil enzyme activity, tuber yield and quality. Three different planting densities of chili peppers in chili peppers and cassava intercropping (T₁, T₂ and T₃, with the spacing of 0.4 m, 0.5 m and 0.6 m, respectively) were designed. The results showed that the aboveground growth indexes of cassava under intercropping treatment had different degrees of inhibition in various growth periods of cassava, and the inhibitory effect deepened with the increase of density and time, so the aboveground plant height and stem thickness of T₃ treatment were minimally inhibited; intercropping treatments were able to improve the relative chlorophyll content of cassava seedling leaves, and the intercropping treatments were able to increase the net photosynthetic rate of the whole period of potato production, stomatal conductance, and the cytosolic rate of the tuber expansion period, and intercellular carbon dioxide concentration during tuber expansion, but had no significant effect on the transpiration rate of cassava in all growth periods; intercropping treatments significantly increased the activities of soil urease, acid phosphatase, catalase and sucrase compared with CK, and the activities of the soil enzymes were significantly higher than those of other intercropping treatments by T₃ except for the activity of soil catalase which had no significant difference among the intercropping treatments; intercropping reduced the aboveground biomass and belowground biomass, and the activity of soil enzymes by T₃; intercropping reduced the relative chlorophyll content of cassava leaves at seedling stage. Although intercropping reduced the above-ground biomass and the number of cassava tubers in the below-ground part, it could improve the weight of cassava, and there was no significant difference between intercropping T₁ and T₂ treatments and the yield of CK, while the acreage yield of T₃ was significantly increased by 13.98%; intercropping could effectively improve the quality of tubers, and the contents of various qualities other than soluble sugar and cellulose in T₃ treatment were significantly higher than that of other treatments, among which, the intercropping treatments were able to increase the starch content of cassava tubers to different degrees, respectively, and increased the starch content of cassava tubers to different degrees. Among them, intercropping treatments were able to increase the starch content of cassava tubers to different degrees, which was increased by 13.06%, 8.25% and 19.33% respectively. In summary, cassava intercropping can improve the yield and quality of cassava tubers by increasing the photosynthetic rate and soil enzyme activity of cassava, and then increase the economic benefits of cassava. Finally, the T₃ treatment with 2 rows of cassava and 2 rows of chili peppers (plant spacing 0.6 m) had the optimal cultivation density, which was a suitable cassava-chili pepper intercropping pattern for Hunan production area.