The invention puts forward a linear transformer table family multistage line loss analysis method and system based on same-period data. The method comprises the following steps that: according to obtained linear transformer table family basic equipment information and a power distribution network, collecting information data, setting a cut-through analysis rule for relevant data to which the same-period data relates to realize same-period cut-through association analysis, automatically carrying out association analysis in fixed time, outputting a linear transformer table cut-through abnormal data inventory, and forming an equipment set and a cut-through set; through line loss day monitoring, realizing double-high-loss analysis on a distribution line and an area line loss, and forming a monitoring set and an abnormal set; utilizing a system clustering analysis method to analyze a key factor which influences the line loss to form a clustering set; utilizing a positive and negative correlation analysis method to realize the influence analysis of a user for the distribution line and an area line loss rate, and forming a relevant set; and generating a linear transformer table family multistage analysis matrix graph. By use of the method, the detail inventory of each factor set can be provided so as to be favorable for quickly carrying out auxiliary analysis of abnormal problems, andtherefore, various auxiliary reference decisions are provided for the line loss governance of business personnel in time.