Co-fermentation of lignocellulose-based carbohydrates is a potential approach to improve the economics of microbial lipid production. To obtain an industrial strain that metabolizes glucose and xylose with a higher microbial lipid production, the strain Mortierella alpina was mutated by low-energy ion beam implantation. After nitrogen ion beam implantation, a mutant strain, M. alpina I502-8 (MAI502-8), was obtained. MAI502-8 was an efficient producer of microbial lipid from glucose and xylose (5: 3 wt/wt). Moreover, the co-fermentation conditions were also optimized. Under optimal conditions, the maximum yield of bio-mass and microbial lipid reached 27.4 and 10.05 g L-1, respectively, which were 2.38-fold and 1.84-fold those in the initial media. Of the mixed sugar, 84.33% was used up during co-fermentation.