The invention relates to line loss monitoring technology, in particular to a line loss monitoring method based on a real-time database. The line loss monitoring method based on the real-time database solves the problems of poor monitoring instantaneity, low mentoring result accuracy degree, high monitoring workload and low monitoring efficiency of existing line loss monitoring methods. The line loss monitoring method based on the real-time database is implemented according to the steps that 1) the output end of a data acquisition module is connected with the input end of a database module, and the output end of the database module is connected with the input end of a data analysis and processing module; 2) the data analysis and processing module calculates a maximum theoretical line loss value and a minimum theoretical line loss value of a line according to entered basic data; 3) the data acquisition module acquires real-time operating data of the line; 4) the data analysis and processing module calculates a real-time line loss value of the line according to the invoked real-time operating data and then compares the real-time line loss value with the maximum theoretical line loss value and the minimum theoretical line loss value. The line loss monitoring method based on the real-time database is applicable to line loss monitoring.