This study aims to investigate the changes in area ratios by space through floor plans of national leasing houses constructed by the LH in Jangseong-gun, particularly focusing on the floor plans of public leasing housing complexes built during the 1970s-80s and those during the 2010s. The results are as follows: First, according to the composition ratio of floor plans by period, the type of Bedroom> Livingroom> Common Area> Kitchen+Dining> Multi-purpose room> Bathroom> or the type of Bedroom> Livingroom> Kitchen/Dining> Common Area> Bathroom> Multi-purpose room were found to be high during the 1970s. Whereas, the type of Common Area>Living room(Kitchen/Dining included)>Bedroom>Bathroom>Front Entrance was found to be high during the 2010. It can be concluded that the ratio of Bedroom and Living room was found to be high during the 1970s, but after 2010s, the spacial composition ratio of Common Space, Living room, and Bedroom is getting higher in the order. Second, in terms of the composition ratio of floor plans by the area of unit household, among the floor plan of C-1, B-2, B-3, C-2 which were used since 2010s, the spatial ratio of Bedroom was maintained in the range of 20%; while during the 1970s, the Bedroom space of A-1(46%), A-2(46%), and A-3(41%) was found to be higher than 40%. It can be concluded that the size of bedroom space has doubled over time. In terms of the changes in the spatial ratio of Living room, A-1(15%), A-2(22%), and A-3(23%) were found during the 1970s. Compared to the recent floor plans of C-1(28%), B-2(25%), B-3(33%), and C-2(34%) which are applied in Jangseong-gun, Jeollanam-do province, no big changes have been found, particularly in the small floor plans (20% range).