This study focused to discuss with religious education for children, based on Montessori’s religious education by Catholicism. The religious view of children in Catholicism is showed in the Gospel according to St. Matthew 11:15 “... This all revealed to children…, you cannot enter if not you become like children.” This expression publicize that child is a spiritual fetus and has the good distinct of religious. It is the best religious education for children, to teach them to live similar to the life of Jesus Christ. Therefore, this study aims that children are provide the prepared environment, Atrium as the place of religious education and than they show their spirituality. This process allow them to reveal the religious belief in the Atrium, they practice the life of Jesus Christ, including his birth, death, and rebirth according to Calendarium Liturgicum. It is similar to the process to accomplish their goals through the their curriculum in early childhood education. Regardless of religious sects, Montessori’s religious education aids children to cultivate their spirituality that is immanent in the inside, to fill with energy, and to live peacefully. For this, Montessori provides the interpretation of children’s religious instinct, the understanding of differentiation their religious belief to spirituality, and the way to practice the religious education by analyzing the relation of children’s spirituality and other sciences. We should serve the prepared environment for children’s peaceful life in early childhood. And it is possible to practice religious education, cosmos education, peace education, and ecological education.