The bamboo leaf ultrafine powders were obtained by ball milling. The physicochemical properties and antioxidant activity of different particle sizes of bamboo leaf ultrafine powders were studied. The results showed that the smaller the distribution of granule diameter, the lower the flowability and density, but the higher the dissolvability. When the smallest particle size, and that was when the bamboo leaf powder was obtained by ball milling 5 hr, the content of polysaccharides, proteins, total phenols, and total flavonoids were higher than other powders. According to the scanning electron microscopy (SEM), the surface of bamboo leaf powder pretreated by superfine pulverizing was rough and collapsed. In addition, the DPPH· and ABTS· scavenging ability of bamboo leaf powder increased with the decrease in the particle size. It can be concluded that the ball milling technology is conducive to increase the yield of active substance and the antioxidant activity of bamboo leaves. Practical applications The modified method of superfine comminution significantly improved the physicochemical and antioxidant activity of bamboo powder. Therefore, superfine comminution would be a nice choice for the production of ultrafine powder from bamboo leaf. In addition, the active bamboo leaf ultrafine powder can be incorporated into other food products for enhancing textural properties and promoting favorable mouth-feel because the addition of polysaccharides, proteins, total phenols, and total flavonoids from bamboo leaves is associated with certain food properties.