The small-leaf ash tree, also known as Sophora japonicus and Qinpi, belongs to the family Oleaceae. Ash is a small tree with a height of 5 meters. Branchlets are light brown, with finely pubescent hairs.

The leaf length is 4-11 cm; the leaflets are 5-7, stalked, ovate or round-ovate, 2-4 cm long, blunt or short acuminate at the tip or close to the tail tip, broadly wedge-shaped at the base, with blunt serrations at the edge, Both sides are hairless. The panicle is 5-8 cm long, slightly pubescent; the calyx is small, 4-lobed, and the lobes are pointed; the corolla is 4-lobed or completely separated; the stamens are longer than the petals. The samara is narrowly oblong, 2.5-3 cm long, with a blunt or slightly concave tip.

Flowering in May; fruit maturity in September. Distributed in Liaoning, Hebei, Henan, Shanxi, Shaanxi and other places. Small-leaf white wax is an ancient tree species left over from the end of the Tertiary to the Quaternary of the geological age, and is known as the "Living Fossil of Broadleaf Forest". It has a long history of cultivation in our country, but the virgin forest is hard to find. The warm and humid Kashgar River Basin is the fertile soil for its growth.