A large-scale purification of salvianolic acid B from Salvia miltiorrhiza Bunge is presented. The method development began with selection of the solvent system, then optimization of the operating parameters and ended up with linear scale-up from an analytical to a preparative instrument. Three factors were used for method optimization and scale-up estimation: purity, process throughput and process efficiency. Preparation was achieved using a two-phase solvent system comprising hexane-ethyl acetate-methanol-acetic acid-water (1:5:1.5:0.00596:5, v/v). This preparation yielded 475 mg of salvianolic acid B with a purity of 96.1% from 1.5 g of crude extract. The process throughput of crude was 2.23 g/h while process efficiency per gram of target compound was 0.769 g/h. Two factors-process environmental risk factor and process evaluation factor were used for evaluation of the separation process.