The invention discloses an EIT (electrical impedance tomography) lung imaging method based on a 3D accelerometer. The method comprises steps as follows: posture position information of a to-be-detected person is collected by the 3D accelerometer in real time and is transmitted to a controller of an EIT lung imaging system together with current electrode information; the controller judges whether the position information is changed according to the posture position information, and when the position information is changed, new position information is input into an image synthesis model, so that a new image synthesis algorithm is obtained; the currently collected electrode information is input into the new image synthesis algorithm, an image file is formed, finally, the image file is processed, and a tomographic image of the lung function is obtained and displayed by a terminal. The 3D accelerometer is adopted to collect the posture position information in real time, so that a doctor is not required to input related posture information manually and frequently; besides, the calculating accuracy of the 3D accelerometer is high, accordingly, continuity of an intensive care process is guaranteed, and the problem of inaccuracy caused by the fact a patient changes the posture himself in a long-term intensive care process is solved.