The invention relates to an electric power system line weakness evaluation system and method based on multi-attribute analysis. The system comprises an EMS information obtaining module, a line topology importance degree calculation module, a line correlation coefficient calculation module, an economic loss calculation module, a hidden failure rate calculation module, a line integral weakness calculation module and a weak line screening module. The method comprises the following steps of obtaining trend information and historical information of each line in an electric power system; obtaining the topology importance degree index of each line, the correlation coefficient index of each line, the hidden fault rate index of each line and the economic loss index of each line due to line breaking according to the trend information and the historical information of the line; building an integral weakness index function; performing calculation by using the topology importance degree index, the correlation coefficient index, the economic loss index and the hidden fault rate index of the line as input data of the integral weakness index function to obtain the integral weakness index of each line; and obtaining the weak line in the electric power system through setting the critical weakness index.