Abstract: The amplified method is commonly used to construct large-scale designs with excellent properties. In this paper, the space-filling properties of Triple designs with amplified structure are discussed under the maximin L_2-distance criterion, and an upper bound on the maximin L_2-distance of Triple designs is obtained. A fast computation method of the generalized wordlength pattern of the Triple design is obtained based on the wordlength enumerator, and a lower bound on the wordlength enumerator of the Triple design is obtained. Numerical examples show that the Triple designs have good space-filling properties, both the upper bound of the maximin L_2-distance and lower bound of wordlength enumerator are attainable.