1. The flowering time of Robinia pseudoacacia and Sophora japonica is different with different flowering periods. Among them, the flowering period of Robinia pseudoacacia is April-May, and the flowers are white butterfly flowers with axillary racemes, while the inflorescence of Sophora japonica is usually terminal and pyramidal, which usually blooms in July-August every year.

2. The leaves of Sophora japonica with different leaf shapes are oval, with sharp apex and rounded base, while the leaves of Robinia pseudoacacia are oval, with round apex or slightly concave, so it is very easy to distinguish Robinia pseudoacacia from Sophora japonica in leaf shape.

3. Robinia pseudoacacia is a strong positive tree species, which is not suitable for growing in shady environment, likes dry climate and is not resistant to water and humidity, while Sophora japonica is cold-resistant, sunny and has certain shade tolerance, and its root system is prone to poor growth in low-lying areas.

4. The main producing area of Sophora japonica is the north of China, which usually grows on the North China Plain and the Loess Plateau at an altitude of 1 meter. Robinia pseudoacacia originated in North America, and now most of it grows near the Yellow River and Huaihe River basins, which is suitable for planting in plains, hills and other places.