Recently, Ri, Hamano and Nakagawa have experimentally revealed adsorption effect transistor characteristics of ZnO sinters [Yogyo-Kyokai-Shi, 93, 230-36 (1985); Yogyo-Kyokai-Shi, 94, 419-24 (1986)]. These results are computationally simulated for the sinters having the local states of bulk donors, grain boundary interface acceptors, surface acceptors and thermally desorbable surface donors in conformity with Fermi-Dirac's law for electron occupation, Poisson's equation for potential distribution and charge neutrality condition. Each parameter of the local states is concurrently obtained within the reasonable value. The potential barrier at necks with radius larger than the surface Debye length is weirlikely formed because of the interface and so independent of the surface states (open-out necks). The potential barrier at necks with radius smaller than the surface Debye length is formed in the shape of a saddle because of both the surfaces and the interfaces and so depends on the neck radius and the surface states in addition to the interface states. The bulk resistivity of sinters is obtained by the effective medium approximation for random networks in consideration of the neck radius distribution. The clusters bonded by the open-out necks percolate always through the sinters above 85% in the relative density. On the basis of the above, the hysteresis of bulk resistivity and adsorption effect transistor responses to admission of propane gas are analyzed.