Photosynthetic compensation is an effective strategy for optimizing light energy utilization in heterogeneous light (HL). However, it is often impaired, and the involving mechanisms remain unclear, particularly in C ₄ plants. When maize ( Zea mays L.) cultivars with different photosynthetic compensation capability were exposed to HL, P _n of shaded leaves (S-leaves) decreased in both cultivars, while the P _n of unshaded leaves (US-leaves) increased in RY1210(RY) and decreased in ZD808(ZD). Results also showed increased SPS level, decreased AGPase level, and reduced Trehalose-6-phosphate (Tre6P) content in US-leaves of both cultivars, indicating enhanced flux from triose phosphate (TP) to sucrose synthesis under HL. In addition, SUTs and SWEETs levels of US-leaves increased in RY, while they decreased in ZD. This result implies that the sucrose export from the US-leaves of plants with photosynthetic compensation was enhanced. In US-leaves of ZD, restricted sucrose export led to increased sucrose and starch, accompanied by a substantial rise in TST2/ SUT2 and extensive accumulation of sucrose in vacuoles. In summary, photosynthetic compensation involves enhanced flux from TP to sucrose synthesis and increased sucrose export in US-leaves. In this process, Tre6P may function as a systemic signal modulator, regulating sucrose synthesis in source leaves and phloem loading. The increased sucrose storage in vacuoles may delay the Tre6P perception of sucrose levels induced by HL, which ensures the increased flux of sucrose synthesis.