Abstract: To study the effects of systemic signals generated by the top leaves of maize seedlings on the photosynthetic induction of bottom leaves, and to explore the possible mechanism of efficient utilization of light spots by maize leaves. Taking maize（Zea mays L.）seedlings as experimental materials, the photosynthetic induction process of the bottom leaves of maize seedlings was measured by Li-6400 portable photosynthetic apparatus.The time required for the photosynthetic induction process from the lowest to the highest in the top leaves of maize seedlings was significantly shortened by pre illumination, and the T50 and T90 of the middle leaves decreased, respectively, while the T50 and T90 of the bottom leaves decreased by 29% and 37%, respectively. Under all the shading conditions,spraying hydrogen peroxide（H₂O₂） on the bottom leaves could also promote the process of photosynthetic induction. Even if the top leaves were pretreated with trichloroacetic acid（TCA） and diphenyl potassium iodide（DPI）, the process of photosynthetic induction could not be changed even if the top leaves were pretreated with DPI. Preillumination on the top leaves of maize could produce systematic signals, and the signal substance was H₂O₂, which was transported through phloem. In this way, the photosynthetic induction process of other leaves could be regulated, which was conducive to the utilization of dynamic light energy and carbon accumulation in the bottom leaves of maize. This system signal plays an important role in the efficient utilization of light spot in the lower leaves of maize canopy.