Most of the evolutionary algorithm researches related to diversity maintenance scheme are dedicated to the diversity of objective space and ignore the diversity of decision space.This arrangement could lead to excessive diversity in the objective space but poor diversity in the decision space.To address this issue

this paper proposes a two-space-density based multi-objective evolutionary algorithm.Two-space-density is defined to reflect the diversity in both the objective space and the decision space.Based on two-space-density

TSD-mating selection is presented to balance the convergence and the diversity of population;TSD-selection is designed to fully explore the objective space and the decision space.The experimental results show that our algorithm performs competitively against the chosen state-of-the-art designs.