In order to improve the content of linear maltooligosaccharides with specific degree of polymerization in the enzymatic hydrolysis products, the effects were investigated including from the membrane separation, activated carbon adsorption separation, sephadex column chromatography and ion exchange resin column chromatography. The results showed that the membrane separation, activated carbon adsorption separation, sephadex column chromatography and Na⁺/Ca²⁺ ion exchange resins were all not conducive to continuous batch operation. In contrast, K+ ion exchange resins had better effects. Compared with the initial enzymatic hydrolysate, the proportion of G3~G6 and G5+G6 in the permeable solution after separation and purification by K+ ion exchange resin increased by 39.53% and 8.13%, and the recovery reached 78.11% and 63.89%, respectively. In addition, the purity and recovery of G3~G6 and G5+G6 in the end product were further improved by using the simulated moving bed with K+ ion exchange resin as fixed phase adsorbent. This study can provide a reference for the continuous separation and purification of straight malt oligosaccharides in industry.