【Objective】 Imidacloprid, a new type of neonicotinoid insecticide with high pest control efficiency, is widely used in recent years. As this chemical insecticide has a long residual period (about 25 days), it is necessary to evaluate risks it might pose to beneficial microbes in the soils. 【Method】 Solid and liquid incubations were carried out simultaneously to investigate effects of the insecticide on growth, reproduction, and phosphorus (P) dissolving capacity of inorganic phosphate-solubilizing bacteria (IPSB), such as Burkholderia Yabunchi B05, B07 and B09, relative to concentrations of imidacloprid (0, 5, 10, and 20 mg•L^-1). 【Results】 Imidacloprid inhibited to a varying extent the growth and reproduction of all the three strains of IPSB, with the diameter of bacterial colonies decreased by 39.81%~55.45% in solid incubation. The tested bacteria varied in solubilization of tricalcium phosphate in response to imidacloprid. B09 was lowered in diameter of P-dissolving halos and index in the presence of imidacloprid, but B05 and B07 behaved otherwise, with the diameter of P-dissolving halos and index reaching as high as 9.72% ~19.44% and 40.69%~106.94%, respectively. In liquid incubations, imidacloprid also inhibited growth and reproduction of the three strains of IPSB, with the bacterial density decreased by 49.87%~65.28% in culture solutions. P solubilization capacibility of the bacterial strains varied with imidacloprid concentrations. Imidacloprid, regardless of concentration, stimulated P solubilization of B05. P solubilization of B07 varied in solutions low or mediumin concentration of imidacloprid, but increased in those high in imidacloprid concentrations compared with CK (without imidacloprid). B09 showed a similar tread to B07 in variation of P dissolving capacity in solutions low in imidacloprid concentrations, while it decreased greatly in solution medium or high in imidacloprid concentrations. All the three strains of bacteria were able to excrete protons, oxalate, and citrate. Oxalate and citrate accounted for 67.65%~83.28% of the total organic acids excreted. In addition, acetate was detected in culture solution with B05 and B07, malate with B09, and succinate with B07. Excretion of the organic acids was affected by not only imidacloprid concentration, but also strain of bacteria and type of organic acid. Furthermore, imidacloprid inhibited bacterial proton secretion by a varying degrees. The amount of P dissolved from tricalcium phosphate was positively related to the excretion of total organic acids (r = 0.876, P < 0.05, n = 12) and to that of protons (r = 0.823, P < 0.05, n = 12) as well. 【Conclusion】It could be concluded that imidacloprid inhibites growth and reproduction of the IPSB by a varying degree in the soil, thus affecting the effects of the bacterial excreting organic acids and protons, and hence the effect of promoting or inhibiting and P solubilization. So in pest controlling application of a large amount of imidacloprid could influence the activities, numbers, and functions of IPSB to a various extent, depending on type of the soil and group of IPSB.