In order to find out the ratio of silicon and calcium fertilizer suitable for the cultivation of passion fruit in the low-heat valley area of Guizhou, this study took passion fruit Qinmi No. 9 as the test material. The experiment was conducted with 50 g of silicon fertilizer per plant before flowering, spraying calcium fertilizer about 10 days after flowering, spraying once every 15 days, spraying three times continuously, and the concentration of calcium fertilizer was 500 times, 1000 times and 1500 times. CK was used as the control group, which received no fertilizer application. The effects of different medium and micro fertilizers, as well as dosages, on the quality and related cell wall metabolism indexes of passion fruit were explored by applying silicon fertilizer to the soil and spraying calcium fertilizer during the flowering and fruiting periods. The aim was to screen for the best specialized silicon-calcium fertilizer formula. The aim is to provide a theoretical basis and practical guidance for improving the quality of passion fruit. The results showed that compared with the control, soil application of silicon fertilizer and spraying calcium fertilizer 1000 times combined application increased the single fruit weight, fruit hardness and fruit shape index of passion fruit. Additionally, they elevated the content of soluble solids (TSS) and vitamin C (Vc), while reducing the content of titratable acidity (TA). Furthermore, there was an increase in soluble sugar (SS) and soluble protein content (SP). Peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activities were promoted. However, the activities of water-soluble pectin (WSP) content, cellulase (CX), polygalacturonase (PG), and pectin methylesterase (PME) decreased due to the increase in protopectin and cellulose in the peel, each index was significantly different from the control group. It shows that silicon-calcium fertilizer had the best effect on enhancing passion fruit quality and improving the mechanical strength, toughness and stability of peel. Compared to CK, the single fruit weight, fruit hardness, longitudinal diameter and transverse diameter increased by 11.15%, 27.18%, 6.23% and 3.29%, respectively. Moreover, the contents of TSS, Vc, SS and SP increased by 16.95%, 16.12%, 20.57% and 24.55%, respectively, while the content of TA decreased by 36.03%, and the activities of POD, SOD and CAT increased by 13.16%, 19.67% and 21.65%, respectively. The content of protopectin and cellulose in peel increased by 19.29% and 17.19%, respectively. Meanwhile, the content of WSP decreased by 10.63%, and the activities of CX, PG and PME decreased by 8.58%, 22.98% and 7.52%, respectively.