Based on the interference of parallel light passing through a double prism, a method for measuring the refractive index and concentration of solutions based on interference fringe displacement was proposed, and a platform for real-time capture of interference fringe translation videos and output of translated pixel numbers was constructed. By measuring the refractive index of sucrose and salt solutions through this experimental platform, calibration fitting curves of refractive index versus concentration for sucrose and salt solutions were plotted. Based on the calibration curves, the concentrations of sucrose and salt solutions were measured respectively. The relative error range of the concentration measurement results is 0.18% to 0.65%, with a precision of 0.1%. The device excels in measuring the concentration of transparent liquids, boasting simplicity in construction and ease of operation. The high consistency of the measurement results with theoretical analysis further confirms the scientific accuracy and practical feasibility of this method, providing an effective technical means for solution concentration analysis.