Abstract: The effect of calcium lignosulfonate(CL) concentration on contact angle of magnetite interface was measured and analyzed by permeating height method. The absorbance of the solution was measured by ultraviolet visible spectrophotometer, and then the adsorption isotherm, kinetics of CL on the magnetite surface were investigated with residual mass fraction method, and the infrared spectra of magnetite with or without absorbed CL were also studied by the infrared spectrometer. As a result, with the increase of the CL concentration, the contact angle decreases gradually. The chemical absorption of CL on the magnetite surface is found, which is adsorption with mono-molecular layer, and the adsorption isotherm at diffrent temperatures meets the Langmuir model. The adsorption process reaches equilibrium in 20 min, and the adsorption increases with the increase of temperature.