This paper deals with a mechanical model to simulate the random hysteretic characteristics of wooden frame structure precisely. The first part describes a universal modeling method based on load-deflection relations obtained from static cyclic loading tests. This modeling method, which is called extended-normalized-characteristic-loop (ENCL) model, is capable of obtaining numerous model parameters automatically from cyclic load-deflection relations and simulating hysteretic energy dissipation precisely. The second part includes static random loading tests to confirm the internal hysteretic characteristics of normalized characteristic loop of the structure. In view of the property, the rule of stiffness-degradation due to a repeated random loading was also discussed. The last part is analytical study to confirm the availability of the proposed ENCL model to simulate seismic response behaviors of a structural plywood wall that is subject to an inertial loading test. It is shown that the computed results with use of the proposed ENCL model are in good agreement with the experimental results.