【Objective】Coptis chinensis is a medicinal herb traditionally cultivated and used for many centuries in China. As it is now cultivated extensively in large areas and often continuously for years in a row, sustainable development of the industry has come across serious obstacles caused by mono-cropping. it is, therefore, essential to explore allelopathic effects of this medicinal plant on soil microorganisms, in order to understand mechanisms of the occurrence of obstacles in the mono-cropping and provide certain scientific basis for lifting the obstacles. Method】To that end, an indoor experiment was carried out culturing three strains of inorganic phosphorus dissolving bacteria, B05, B07 and B09 of Burkholderia Yabunchi bacteria, using the solid and liquid culturing techniqu, During the experiment, extract of fibrous roots of C. chinensis (ERC) was spiked to explore allelopathic effects of the extract on growth, reproduction, and tricalcium phosphate dissolving capacity of the three strains. Fresh C. chinensis roots were soaked in deionized water at 251 C for 24 h to extract active components, and then the solution was filtrated through a 50 mol L^-1 filter, and diluted to ERC 0.1 g L^-1. For spiking of the extract, the experiment was designed to have four treatments, i.e. 0 (CK), 500 (low concentration), 1 000 (middle concentration), and 2 000 mg L^-1 (high concentration). 【Result】Results show that the higher the concentration of the ERC, the smaller the size of bacterial colonies, the diameter of P-dissolving halos and the lower the P-dissolving index on the solid culture medium. ERC also inhibited the growth and reproduction of iPDB in variable degrees, reducing the population of iPDB by 35.98%~52.98% in the liquid culture medium as compared with the blank control (without ERC). All the three strains of bacteria tested in the liquid culture released protons, oxalate, and citrate into the solution. Besides, acetate was found in the culture solution with B05, malate with B09, and acetate and succinate with B07. In addition, iPDB varied greatly in tricalcium phosphate dissolving capacity in the culture solution. The mean amount of P dissolved was 228.31 mg L^-1 for B05, 311.64 mg L^-1 for B07, and 174.89 mg L^-1 for B09. Inorganic P dissolution by these bacteria was positively related to efflux of proton (r= 0.877, p 0.05, n= 12) and organic acids (r= 0.604, p 0.05, n= 12). When ERC inhibited efflux of protons and organic acids in culture solutions, it reduced P dissolution by 21.68%~60.55%. 【Conclusion】 During the growing period, C. chinensis roots released allelopathic chemicals, which affected adversely community structure and physiological and ecological functions of the iPDB, thus reducing bio-availability of inorganic P in the soil, which could be one of the possible reasons why obstacles occur in mono-cropping of C. chinensis.