The invention discloses a method for determining the correlation of line loss rate influencing factors. The method is characterized in that an objective function aiming at the minimum annual cost per unit area of power supply is proposed, and influencing factors of the line loss rate are set to be variables to be optimized of the objective function; optimized variables of a distribution network under different load densities are acquired by using the proposed objective function under the condition of meeting the voltage loss allowed by lowest-level distribution lines, thus a calculation formula for the line loss rate of the distribution network is built, and finally an influencing law of each single influencing factor for the line loss rate is acquired by using a correlation function according to the line loss rate. The method disclosed by the invention can calculate the correlation between each influencing factor and the line loss rate, has high reference and can provide reference for energy conservation, loss reduction, upgrading and reconstruction of the distribution network.