The invention discloses an organic extraction phase for extracting a lactic acid from a heavy phase lactic acid, comprising an extracting agent, a solvent, and a phase regulator. The organic extraction phase provided by the invention can extract over 99% of the lactic acid in the heavy phase lactic acid into an organic phase, so that a refined lactic acid or lactate can be produced by using the heavy phase lactic acid with a simple process route and low production cost.