If you apply for public housing in Hong Kong, but you already have a property in the Mainland, will it be found out (the owner of the property in the Mainland is the spouse of a Hong Kong resident)?

One country, two systems means that there is no mutual inspection right in economic and other aspects, only cooperation and no intersection. These are two customs areas. You see, many things are considered overseas. In this respect, buying a house in the mainland is the same as buying a house in the United States, so don't worry, it doesn't matter.