Abstract: At present,seldom evaluation methods can be found for the performance of electronic let-off device of high speed shuttleless loom.This paper has proposed that the two indexes,i.e.,the extreme unevenness and similarity be used to evaluate the consistency of tension change degree and tension fluctuation,and then the advantages and disadvantages of the performance of an electronic let-off device was evaluated.The two indexes were used to compare the performance of electronic let-off devices of Peogalo OMNI-190 and Toyato JAT710 when weaving fabrics with different covers or with similar specifications.The results show that the performance of the electronic let-off devices of two different looms is stable.There are no significant differences between the two.