The present invention relates to a post extraction process for preparing low acyl gellan, comprising the steps: deacylation treatment of gellan gum-containing fermentation broth, enzyme treatment, flocculation of low acyl gellan gum with divalent or polyvalent metal cations, clarification treatment of gellan gum solution, dehydration treatment of gellan gum solution, removal of divalent or polyvalent cations and decoloration, and drying and milling. Preferably, the process comprises the step of formulating a proper amount of chelating agent/acid system before the drying and milling step to chelate the added additional divalent cations added during the use of gellan gum, and at the same time to keep the pH value in a relatively stable condition. The present invention also provides the various low acyl gellan gums prepared by the above methods. The product has the following characteristics: a good appearance, a high transmittancy, and high gel strength. In particular, the chromaticity of the product is above 83%, the transmittancy is above 85%, and the gel strength is above 400 g/cm2.