We used Sapindus mukorossi Gaertn. from Jianning County, Fujian Province as material to study fruit growing and development regularities. The fruit growth dynamics were observed, the growth indexes were fitted by logistic equation, the changes of pericarp microstructure during the growth process were observed, and the important stages of fruit growth and development were determined, which could provide a scientific basis for the efficient cultivation and management of S. mukorossi and the formulation of fruit harvesting strategy. The results showed that: (1) the growth of fruit was consistent with the accumulation of pericarp saponins and seed oil, the fruit growth, total saponins in pericarp and seed oil accumulation of S. mukorossi were similar, which generally presented a logistic growth modela single Sshaped curve. The main accumulation periods of total saponins in pericarp and seed oil were 45-90 DAP and 75-105 DAP, respectively. (2) In addition to the basic structures of cuticle, epidermal cells, collenchyma cells, parenchyma cells, vascular bundles and sclereids, the pericarp of S. mukorossi also contained many large lysogenic secretory cavities and calcium oxalate crystals. With fruit growth, the volume of secretory cavities also increased. (3) According to the change regularities of fruit growth and the fitting result of logistic equation, the fruit growth and development process of S. mukorossi fruit could be divided into four stages: early growth stage (0-30 DAP, days after flower pollination), fast growth stage (30-90 DAP), late growth stage (90-120 DAP), and fruit maturity stage (120-150 DAP). Among them, the period of fruit maturity stage was suitable for the harvesting of fruits. The fruits harvested at 135 and 150 DAP were most suitable for the use of pericarp saponins and seed oil, respectively. In addition, the fruit harvesting time should be adjusted appropriately according to the annual weather conditions.