It has been found that human’s faster moral decision-making illuminates their moral characters. Considering that the speed of decision-making is an important attribute that people can perceive about the behavior of intelligent machines, this study aims to explore how the speed of moral decision-making by intelligent machines affect people's trust in them compared to humans. A 2 (decision-making speed) × 2 (decision-making content, moral vs. immoral) situational experiment shows that the presence of moral behavior lead people to trust for both intelligent machines and human beings, but faster moral decision-making increases people's trust in them only by intelligent machines. In addition, human’s competence perception of intelligent machines is found to play a mediating role between the speed of moral decision-making by intelligent machines and people's trust in them. Thus, the current research has indicated that the speed of moral decision-making by intelligent machines can affect people's trust in them, and there are different mechanisms for people's speed perception of moral decision between intelligent machines and human beings.