The invention relates to the field of agricultural machinery, in particular to a multistage suspended airflow type tea grading system adopting flexible mesh belts. The system comprises 4-6 grading units which are connected sequentially, wherein each grading unit comprises a lifting assembly, an air suspension assembly, a flexible mesh belt sorting assembly and an output assembly; each air suspension assembly comprises a falling channel, an air suspension air channel and an air suspension fan; each flexible mesh belt sorting assembly comprises a flexible mesh belt and a rotating shaft, the flexible mesh belt is annular, screening holes are formed in the surface of the flexible mesh belt, the rotating shaft is arranged in a ring of the flexible mesh belt, drives the flexible mesh belt to operate and divides the whole flexible mesh belt into a screening mesh surface and a separation mesh surface, and the screening mesh surface is horizontally arranged; the output assembly comprises a coarse-leaf output belt and a fine-leaf output belt, the coarse-leaf output belt is arranged below the corresponding flexible mesh belt sorting assembly, and the fine-leaf output belt passes through the annular inner ring of the corresponding flexible mesh belt and is arranged below the corresponding screening mesh surface in parallel.