Diazotrophs/plant symbiosis model system has been developed but the nitrogen fixation efficiency of engineering systems was suboptimal compared to the wild-type system. In this study, CDs with benzoquinone structure and phenazine structure that prepared from O-phenylenediamine (o-PD) and catechol (CAT) were selected as electron-donor and electron relay for constructing CDs/microalgae nitrogen fixation hybrid system. the X-ray photoelectron spectroscope (XPS) and Fourier transform infrared spectrometer (FTIR) results demonstrated the presence of C=O bond from benzoquinone on CDs. 1H-Nuclear magnetic resonance (NMR) spectra reveal the fluorescent molecules linking on the CDs’ surface. The photocurrent response demonstrates the photoelectron donor ability of CDs. Nostoc commune Vauch microalgae were selected as a diazotroph. The hybrid system exhibited 1.32 times ethylene-produced content compared to pure microalgae. Linking this hybrid system with the lettuce hydroponics platform, the lettuce successfully utilized the nitrogen in the atmosphere as ammonia fertilizer. The net photosynthetic rate, total fresh weight, total chlorophyll content, and total soluble protein content of lettuce growth in the established platform increased by 1.20, 1.12, 1.14, and 1.32 times, respectively.