Abstract: In this paper,the best technological condition for ultrasonic-assisted extraction pigment from flowers of Robinia pseudoacacia L. was determined by single factor experiments and orthogonal tests. The pigment content from extract solution were determined by pH differential method. Results showed that the optimized extraction conditions were the best extraction agent pH=2 citric acid,the ratio of liquid to material 50:1 mL/g,the extraction temperature 60 ℃,and extraction time 20 min,ultrasonic power 300 W. Under this condition,the field of pigment was 118.77 mg/100 g. The order of factors affecting pigment extraction was:Ultrasonic power>ratio of liquid to material>extraction time. According to the result of characteristic absorption peaks by uv-vis spectrophotometer:Pigment from flowers of Robinia pseudoacacia L. maybe belong to anthocyanin. This study can provide certain theoretical basis for the development and utilization of flower from Robinia pseudoacacia L.