Abstract: In this paper the structure, type, distribution, origin and development process of the blocked laticiferous canals in the bark of Rhus verniciflua Stokes are studued. These laticiferous canals are blocked with parenchyma cells alone or with both parenchyma cells and cork cells. These block cells are derivatives of the epithelial cells and the sheath cells. These cork cells are as form as storied cork. The block laticiferous canals may be divided into two main types:The homocellular block type and the heterocellular block type. The phenomenon of the obstructed laticiferou canal typifies a lacquer tree in age. And furthermore our study of the block laticiferous canals may provide some useful information for the theory of the structure of the laticiferou canal, systematicis of lacquer tree, regeneration of lacquer and the production of lacquer.