The effects of glycine betaine(GB)(one of compatible solutes) on the morphology of Lactobacillus plantarum under high osmotic pressure were studied.Co-immobilized GB with lactic acid bacterium,Lactobacillus plantarum,were used in a pilot scale high salt liquid-state soy sauce fermentation process to improve the conversion rate of the protein and shorten the fermentation period.The embedding method of sodium alginate was conducted for the co-immobilizing of GB and lactic acid bacterium into particles which was added to the fermented soy sauce mash,and measured the total acid and amino acid during the fermentation process.It was showed by electron microscopy that Lactobacillus plantarum with GB grew well under high salt condition,and the cell morphology was similar to the one with normal culture.The soy sauce pilot showed that,compared to the normal control group,the amino acid nitrogen of the co-immobilized group increased 0.234 g/100mL,the total nitrogen content increased 0.358 g/100mL,and the amino acid conversion and protein utilization increased by 1.7% and 6.7% compared to the normal control group.The fermentation period for co-immobilized group was shorten by 1 week compared to single fixed lactobacillus group and the test group with addition of free lactobacillus and betaine,and this phenomena was more obvious compared to blank group.It's concluded that co-immobilized GB with lactic acid bacteria has positive effect on soy sauce brewing process.