This study set out to examine the social and economic causes of 2019 Hong Kong Protests instead of political ones as media and researchers reported that the Umbrella Revolution of Hong Kong in 2014 began with a political cause but had Hong Kong citizens’ social and economic complaints at its root. 2019 Hong Kong Protests also began with political causes including the Fugitive Offenders amendment bill and the guarantee of the Hong Kong system, but there are more and more data reporting that the deterioration of Hong Kong citizens’ social and economic life worked at the bottom of the protests. The present study focused on new immigrants under the ultimate goal of investigating the effects of increasing new immigrants on the lives of Hong Kong citizens. The results were as follows: first, the number of new immigrants was reduced recently. Recent data shows that the accumulated number of new immigrants amounts to 1.50 million, but the number of new immigrants with the settlement pass and that of inadmissible immigrants are dropping gradually in recent years; secondly, the study examined the economic state of new immigrants and found that their participation rate in labor continued to rise. The proportions of immigrants are increasing in service and sales and non-skilled labor, which will affect Hong Kong citizens that have worked in low-wage jobs. The income of new immigrants is rising, which means that their settlement in the Hong Kong society is accelerating; and finally, a look at the social state of new immigrants reveals that supports for the Comprehensive Social Security Assistance are decreasing over time with no big increase in expenditures. The percentage of public housing is dropping among new immigrants, whereas that of individual homes is rising among them, which indicates that their penetration into public housing, which Hong Kong citizens had concerns with, is not happening. Like income, the settlement of new immigrants in Hong Kong housing is intensified. In addition, the population using Putonghua is growing in Hong Kong. These results suggest that new immigrants are competing against Hong Kong citizens in economic aspects including employment and participation rates in labor in the Hong Kong society. There are, on the other hand, no negative influences including growing expenditures for new immigrants in Comprehensive Social Security Assistance. New immigrants do not violate the right of Hong Kong citizens in housing welfare including public apartments. Rising income, growing percentage of individual homes, and increasing use of Putonghua indicate that new immigrants have become stable in their settlement in the Hong Kong society. It means that the growing number of new immigrants has not exerted as negative effects on the lives of Hong Kong citizens as the citizens’ concerns.