Abstract: The calculation method of power transmission and transformation engineering mainly relies on two-dimensional drawings and manual calculation to complete the engineering quantity estimation. Due to the high redundancy of engineering information, it is difficult to screen the main information, resulting in poor calculation accuracy. In this paper, the whole life cycle graph calculation of power transmission and transformation project based on BIM model is studied. BIM technology is used to carry out 3D modeling of power transmission and transformation engineering, and realize accurate simulation of engineering entity. The principal component analysis method is used to map the component information data, which realizes the data dimensionality reduction and reduces the information redundancy. Ridge regression algorithm is used to carry out feature replacement of component information data to further remove information redundancy and optimize feature space. With the replaced feature subset as the input of MLP algorithm, the whole life cycle graph computation is predicted. In the experiment, the calculation accuracy of the proposed method is checked. The test results show that when the proposed method is used to estimate the quantity of power transmission and transformation engineering, the average consistency ratio of component calculation obtained by the algorithm is 97.5%, which has a relatively ideal calculation effect.