This study focused on the relationship between young children's aggression and associated relative factors, so that we set young children's temperament, young children's self-regulation ability, mother's parenting efficacy, and mother's parenting behavior as associated relative factors. Therefore, we researched how these associated relative factors could affect young children's aggression. Subjects were 350 young children and their mothers who were attending nine kindergarten in I-city and J-city, Jeonlabuk-do. Statistics and methods used for data analysis were Cronbach's alpha, Pearson's correlation and Multiple Regression. Result's are as followings: First, as we researched into the correlation between young children's aggression and associated relative factors, we found that there were significant correlation in young children's temperament and mother's parenting efficacy, mother's indulgent and permissive parenting behavior, and controlled parenting behavior. Second, as we researched into the efficacy between young children's aggression and associated relative factors, we found that young children's aggression was directly affected by young children's active character that is one of young children's temperaments, young children's self-regulation ability, mother's active involvement in parenting behavior, mother's indulgent and permissive parenting behavior, and mother's controlled parenting behavior. That is, young children's aggression was 22% affected by these associated relative factors.