Personally, I think the standards of the middle class should be measured differently according to different cities. For example, in first-tier cities, the proportion of loans to household income should not exceed 30%. The monthly income of husband and wife is about 40,000 yuan, and the deposit is 1.5 million yuan. Having a self-occupied house should be regarded as the standard of the middle class. But in second-tier cities, this standard can be lowered. For example, the husband and wife have a monthly income of about 20,000 and a deposit of about 800,000, which should be more in line with the middle-class standards of second-tier cities.