Abstract: The differentia on response of photosynthesis rate and light use efficiency to light intensity between Soybean and Maize during the prophase, metaphase and anaphase of growth in Northeastern China were investigated and simulated by Michaelis-Menten equation and Dagneli equation. The results showed that both of Michaelis-Menten equation and Dagneli equation primely simulated response of photosynthesis rate to light intensity, and their effect was consilient. But the parameters of maximum photosynthesis, initial quantum efficiency and dark respiration by Michaelis-Menten equation was very distinctly bigger than them by Dagneli equation. However, maximum photosynthesis by Michaelis-Menten equation was even more closed to praxis, and dark respiration by Michaelis-Menten equation was even more closed to praxis. In every phase of growth, maximum photosynthesis and initial quantum efficiency of maize by Michaelis-Menten or Dagneli equation was very distinctly bigger than them of soybean. Light use efficiency rised up as the rising of light intensity then decreaced. The average light use efficiency of soybean was 0.0185 mol/mol, Maize is 0.0281 mol/mol when light intensity was 0~2000μmol/m2/s. Light use efficiency variance was found among different phase of growth. The light use efficiency of soybean and maize was relatively lower in the prophase, rised in the metaphase, decreaced in the anaphase. The light use efficiency of Maize was 1.6 times than that of soybean during whole phase of growth.