The purpose of this research is to compare laws and regulations concerning the density control in collective housing planning in Korea and China and identify any difference between the two countries. The interpretation of such differences is expected to be utilized as basic material for revision and enactment of relevant laws and regulations in the two countries. The comparative analysis in this research has shown that the two countries have significant differences in their legal system on density control such as the ratio of building to land, ratio of floor area to site, distance between two buildings, separation distance from a property line, and setback from road width. The most distinctive difference is that the Chinese regulations consider the length and height of buildings whereas the Korean ones do not take them into account in general. The conclusion can be drawn on the basis of the regulation comparison and simulation design that the Chinese regulations are tougher than the Korean ones. That may lead to a reasonable doubt that Korean regulations excessively allow high density.