An osmotic pump in form of controlled release tablet and the preparation thereof are disclosed Said tablet includes a double-layer tablet core consisted of a drug layer (1) and a push layer (2), a controlled release layer (4) outside the core, an orifice (5) in the controlled release layer (4) and a lubricant layer(3) between the core and the controlled release layer (4). The material of lubricant layer (3) is selected from high-substituted hydroxypropylcellulose or low viscosity hydroxypropyl methyl cellulose. Said method comprises the steps of preparing the double-layer core, coating the core with the lubricant layer (3), coating the controlled release layer (4) outside the lubricant layer (3), then, opening an orifice (5) in the controlled release layer (4) adjacent to the drug layer (1), and obtaining the desired tablets.
