Objective To study the effects of different factors on the salvianolic acid B stability in water solution and to provide the experimental data for production and application of salvianolic acid B. Methods Effects of salvianolic acid B concentration, pH value, temperature, and holding period on salvianolic acid B stability in water solution were studied by the salvianolic acid B changes determined by HPLC in orthogonal design test. Results The most stable condition of salvianolic acid B is that the concentration is 1 mg/mL, pH value is 2, the temperature is 20℃ , and the holding period is one day. Conclusion Salvianolic acid B should be kept in the conditions of higher concentration, lower pH value, lower temperature, and shorter period in solution to ensure its stability.