A field split plot experiment of pineapple was carried out from 2023 to 2024 to explore the effects of nitrogen fertilizer postponing and magnesium fertilizer coupling on the growth and development, yield and quality of pineapple and to provide practical reference for scientific fertilization management of pineapple. The main area was magnesium application rate, namely MgO 0 kg/hm² (M₀), MgO 37.5 kg/hm² (M₁) and MgO 75 kg/hm² (M₂). The sub-area was conventional nitrogen application treatment (N₁) and nitrogen fertilizer postponing treatment (30% of nitrogen fertilizer in slow growth period and flowering period was postponed to rapid growth period and fruit enlargement period, respectively) (N₂). The leaf number, leaf area index, chlorophyll content, dry matter accumulation, yield and quality indexes of pineapple were measured during the key growth period of pineapple. The results showed that compared with N₁, N₂ could significantly increase the contents of chlorophyll a and chlorophyll b in pineapple leaves at mature stage, and increase the number of leaves and leaf area index of pineapple at red stage. Compared with N₁, the dry matter quality and yield at maturity stage increased by 9.40% and 7.65%, respectively, and the vitamin C content and soluble sugar content of fruit were also significantly higher than those of N₁ (P<0.05), while the difference in yield was not significant. Similarly, compared with M₀ and M₂ treatments, M₁ treatment could significantly increase the contents of chlorophyll a, chlorophyll b and carotenoids in leaves, and the leaf number and leaf area index of pineapple at the red stage of flowering increased significantly, thereby improving the dry matter quality and yield at the mature stage, and the difference was significant (P<0.05). The fruit dry matter distribution rate, soluble sugar content, soluble protein content, vitamin C content and sugar-acid ratio under M₁ treatment were significantly higher than those under M₀ and M₁ treatments (P<0.05). Interaction effect analysis revealed that N₂M₁ treatment could increase the content of chlorophyll a, chlorophyll b and carotenoid in pineapple compared with other treatments, and then the number of leaves, leaf area index and dry matter quality increased significantly. Yield increased significantly by 19.43%, 17.39%, 10.07% and 24.96% compared with those of N₂M₀ (P<0.05), N₁M₂, N₁M₁ and N₁M₀, respectively, but not significantly different from that of N₂M₂. The fruit shape index, vitamin C, soluble sugar, soluble protein content and sugar-acid ratio of pineapple fruit treated with N₂M₁ were higher than those of other treatments, and there was a significant difference between N₂M₁ and N₁M₀ (P<0.05). Correlation analysis showed that pineapple yield was significantly positively correlated with leaf number, leaf area index, dry matter accumulation, chlorophyll b content, vitamin C, soluble sugar and soluble protein. There was a significant negative correlation with titratable acid content. N₂M₁ treatment can significantly increase the number of leaves, leaf area index and photosynthetic pigment content of pineapple plants, increase fruit dry matter distribution, thereby increasing pineapple yield and effectively improving fruit quality. Therefore, N₂M₁ could be recommended as the best model for fertilization management of pineapple in tropical regions.