The invention relates to a method for separating and purifying 1,3-propylene glycol from fermentation liquor. The method comprises the following steps: filtering and clarifying fermentation liquor containing 1,3-propylene glycol through a stainless steel membrane separation system, adding dialysis water into the fermentation liquor for dialysis when the fermentation liquor is concentrated by 1 to5 times, and completing the separation and purification of the 1,3-propylene glycol from the fermentation liquor when the amount of final filtrate is 1 to times amount of the fermentation liquor. Compared with the prior art, the separation and purification process is simple and reasonable and has a short procedure and convenient operation. The 1,3-propylene glycol obtained from separation has high purity and high total yield. The stainless steel membrane separation system has low one-time invention cost; and the membrane has a service life as long as above 10 years. The stainless steel membrane separation system has the advantages of low operation cost, high filtration accuracy, high concentration multiple, high bacteria residue concentration, and the like, thereby benefiting the solidification and resource utilization of the bacteria residue, and avoiding secondary pollution.