To improve the accuracy of the state evaluation is the most important for the relay protection state maintenance. Therefore, a fuzzy synthetic evaluation of relay protection based on variable weight value is proposed. The major factor of the device and secondary circuit of relay protection is picked up to establish a reasonable index system of state evaluation. Then according to the variable weight comprehensive concept of factor space theory, the balance function is introduced to adjust the weight coefficient of each factor. Finally, the membership function in triangle trapezoid distribution is got to show the condition information, and synthetic operator is selected, then an objective and accurate evaluation system of relay protection equipment and secondary circuit is proposed. Running examples show that after dealing with the variable weight, some factors weight value become larger or smaller, so running state of evaluate factor may be changed, which makes it close to the real running state.