The relation between the urban structures and radiation processes within 3D canopy layers has been investigated through the experiment by using small-scale models. Concrete blocks (15cm×15cm×15cm) were regularly arranged and the built-up densities were systematically controlled. As a consequence, the following results were obtained;(1) Canopy albedo are significantly influenced by urban structures and seasons. There exists an urban density which gives a minimum values of canopy albedo in each season.(2) The four kinds of representative urban temperature, that is, complete temperature, radiation temperature, satellite temperature and aero-dynamic temperature are compared, and their dependency on canopy densities are discussed.(3) The contribution of heat transfer of each surface is shown.