The invention provides a corrected L-curve electrical tomography reconstruction method based on the second-order differential. The method is suitable for bubble flow tomography and includes the steps that according to a measured field domain, a relative boundary measured value vector b and a sensitivity matrix A which are needed for reconstruction are acquired; through Tikhonov regularization, an L-curve is calculated and drawn; whether a local inflection point exists in the L-curve or not is judged; if the local inflection point does not exist, an optimally-selected regularization coefficient is determined through an L-curve method; if the local inflection point exists, an optimally-selected regularization coefficient is determined through the corrected L-curve method. The method includes the steps that the local inflection point of the curve is determined by calculating a second largest peak value of the L-curve second-order differential, and the regularization coefficient corresponding to the local inflection point serves as the optically-selected coefficient; the regularization coefficient is substituted into Tikhonov regularization, and an image reconstruction inverse problem is solved; imaging is conducted. By the adoption of the method, the electrical tomography inverse problem can be accurately solved, and image reconstruction quality is improved.