All organisms obtain energy and substances through photosynthesis directly or indirectly. This study order to explore the relationship between the photosynthesis daily changes and bulb quality of different cultivars of garlic. Tianshui garlic (TS), Pizhou purple garlic (PZ), Wenzhou small bulb (WX), Henan Nanyang 1 garlic (HN1), Henan Luohe Garlic (HL) were used as the test material. Use field experiments. With the help of CI-340 portable photosynthesis tester and vernier caliper, the photosynthesis-related parameters and bulb (Weight/g, Transverse diameter/cm, Longitudinal diameter/cm) trait data of various cultivars of garlic were measured. The results showed that the daily changes of the net photosynthetic rate and transpiration rate of the five kinds of garlic showed an irregular double-peak curve, the photosynthetic active radiation and leaf temperature all formed a single-peak curve, and the daily changes of the net photosynthetic rate and transpiration rate showed Obvious positive correlation trend, the changing trend of intercellular CO2 concentration is opposite to the changing trend of net photosynthetic rate. All five kinds of garlic have the phenomenon of "photosynthetic lunch break", and the phenomenon of PZ "photosynthetic lunch break" is the most obvious. Each specie's net photosynthetic rate of species in the morning was higher than the net photosynthetic rate in the afternoon. PZ performed well in parameters such as net photosynthesis rate and transpiration rate, and garlic bulb quality was the highest. WX has low water use efficiency and relatively good garlic varieties, indicating that WX has good waterlogging tolerance and can be used as a breeding resource for labour resistance. This study provides a good research foundation for further revealing the garlic photosynthesis mechanism and the analysis of bulb quality.