It is important to clarify the effects of equal carbon rationing of maize straw-derived organic materials on maize growth and nitrogen，phosphorus and potassium uptake and utilization，which is of great significance for the rational use of farmland organic resources. In this study，a maize field experiment was conducted on calcareous brown soil in the eastern part of the Loess Plateau，and three treatments were set up，namely，chemical fertilizer alone control(NPK)，chemical fertilizer with maize straw(NPKS)，and chemical fertilizer with biochar(NPKB)，and the organic materials were applied at C 4 t/hm²，to investigate the agronomic traits and photosynthetic chlorophyll fluorescence parameters of maize at the pulling stage，as well as the composition of yields and nutrient uptake at the harvesting stage，under the conditions of isocarbon rationing. The results showed that the plant height and leaf area of NPKS treatment maize were increased by 14.8% and 29.2%，respectively，and the dry matter weight of NPKS and NPKB treatments maize were increased by 80.8% and 14.1%，respectively，compared with the NPK treatment. Compared with NPK treatment，NPKS treatment significantly increased the transpiration rate，stomatal conductance as well as the maximum photochemical efficiency and the actual photochemical efficiency of maize leaves；NPKB treatment significantly increased stomatal conductance as well as the maximum photochemical effciency and the actual photochemical efficiency of maize leaves，but there was no significant effect on the net photosynthetic rate and transpiration rate. NPKS and NPKB treatments showed a decreasing trend in maize leaf intercellular CO₂ concentration and non-photochemical burst coefficient. Compared with the NPK treatment，maize ear weight，100-kernel weight and yield were increased by 36.4%，31.1% and 45.5%，respectively，in the NPKS treatment；maize ear weight and 100-kernel weight were increased by 18.5% and 15.2%，respectively，in the NPKB treatment compared with NPK treatment. The NPKS treatment significantly increased maize straw nitrogen，phosphorus and potassium uptake and kernel nitrogen and potassium uptake，while the NPKB treatment only increased maize kernel nitrogen and stover potassium uptake. In conclusion，the equal carbon allocation of maize straw source organic matter had a promotion effect on maize growth and nutrient uptake. The equal carbon dosing of maize straw was more favorable to phosphorus uptake of maize than biochar，which promoted maize growth and increased the yield.