Lactic acid has many applications in the food, pharmaceutical, cosmetic, textile and chemical industries. At present, the demand for L-lactic acid has been increasing as a monomer in the production of polylactic acid (PLA) for producing bio-plastic. However, disadvantages of lactic acid fermentation is the high cost of fermentable sugars and the operating cost such as sterilization and separation and purification. The objective of this study is to produce L-lactic acid at low cost raw material by a thermophilic strain Bacillus sp. NL01. Lignocellulosic hydrolyzates containing a high content of glucose, which was prepared from corn stover, was used as substrate for L-lactic acid production. The fermentation was carried out under open condition without sterilization and used NaOH as alkaline neutralizing reagent. In batch fermentation, 56.37 g l-1 L-lactic acid was obtained from lignocellulosic hydrolyzates which contained the solid residues produced in enzymatic saccharification. In fed-batch fermentation, 75.03 g l-1L-lactic acid was obtained from lignocellulosic hydrolyzates supernatant. The yield was 74.5% and the average productivity was 1.04 g l-1h-1. Recently, several Bacillus sp. strainshad been isolated for lactic acid production. In comparison with other Bacillus sp. strains, a relatively better result for lactic acid production was obtained in this study. Besides, all methods used in this study would greatly reduce the production cost. These results are encouraging and demonstrate the feasibility of L-lactic acid production at a low price.