The invention discloses a 1,3-1,4-beta-glucanase mutant, and belongs to the fields of gene engineering and enzyme engineering. Lysine in the 20th position, 117th position and 165th position of 1,3-1,4-beta-glucanase from Bacillus terquilensis mutates through an overlapping extension PCR method to form serine in order to obtain single mutants K20S, K117S and K165S respectively. The above three mutation sites are integrally mutated to obtain a K20S/K117S/K165S triple mutant enzyme. Four mutant enzymes have higher catalysis activity and better thermal stability. Compared with wild enzymes, the above mutant enzymes are in favor of realizing the industrial application.