This review mainly focuses on the role and properties of β-galactosidase in lactose intolerance and its industrial application. β-Galactosidase, hydrolyses the lactose into glucose and galactose and it is most commonly used in food based technology, particularly in the dairy manufacturing industry. This catalyst mainly focus for the improvement of new and novel products with hydrolyzed lactose, which can be appropriate for the lactose-intolerant persons, to improve the technological, texture and scientific properties of non-fermented dairy products. β-Galactosidase derived from the group of saccharides which is a converting enzymes in the family of hydrolases. They are broadly distributed in the several biological living systems. The enzymatic hydrolysis of lactose is also preferred in food based technology due to the low soluble range of lactose. The concentration lactose was found to be high in fermented dairy products such as ice cream, butter, cheese curd, yogurt, etc., can prompt extreme lactose crystallization bringing about items through a coarse, abrasive surface. Lactose hydrolysis in dairy products enhances adaptability also, richness altogether. These products are extra edible. Also for this purpose, the utilization of β-galactosidase enzyme prior to the condensing operation can reduce the lactose content to a point where lactose was no longer a problem industrial application of β-galactosidase. In Industries, due to the positive and constructive effect on intestinal bacterial microflora, different types of applications are possible in β-galactosidase enzyme. © Published under licence by IOP Publishing Ltd.