The invention discloses a method for automatically and designing a pipeline of a power plant, which is used for automatic design of the pipeline in power plant design. According to the method for automatically and designing the pipeline of the power plant, by taking a three-dimensional design system and a two-dimensional data management system as the basis and a two-dimensional engineering system diagram of the pipeline as a data source, under the support of the KKs coding technique and a related master control program, a three-dimensional model diagram of the pipeline is automatically designed and generated. The method for automatically and designing the pipeline of the power plant comprises an information acquisition step, a pipeline data generating step, a three-dimensional model design step and an outputting step. By adopting the technical scheme provided by the invention, the automatic design can be realized on the three-dimensional diagram of the pipeline, and thereby, manpower and material resources are saved, and moreover, the correctness is increased.