Meanwhile, supermarkets’ scale is becoming larger. The evolution of supermarkets is shown in the scale. In the book The Supermarket , Zimmerman (2001, p11-12) limits the scale of the supermarket, that is the business volume should be no less than US$250,000. By 1950s, the number increased to US$375,000. After 1980s, the number is up to US$800,000. 

With the types of commedities enriching and the size expending, a corresponding high-grade service should be offered. Neslin and Leghorn (2006, p. 98) indicate that the first supermarket minimized the costs to ensure the low price of goods, so there’s no additional services at all. With the increasingly fierce competition in the retail industry, the supermarket service projects continue to increase. Especially in supermarkets, they treat service as an important means to distinguish from competitors