Abstract: Whether robot ethics is the ethics of machines or human beings is a controversial issue in the academic circle. In the view of foreign scholars， although there are some relations between robot ethics and machine ethics， they have different research fields. Robot ethics is about how human beings design， handle and treat robots， while machine ethics is about how machines act to accord with human beings' ethical behaviors. Moreover， machine ethics takes machines as the responsibility agent， but robot ethics takes human beings as the responsibility agent. It is of great significance to both of them to clarify the concept of robot ethics and define the research scope of robot ethics and machine ethics. Robot ethics， as an ethics that considers human beings as the responsibility agent， can only be truly realized in the design of robots from the perspectives of analyzing the ethical position of human beings towards robots， the research approach of robot ethics and the institutional guarantee of robot ethics.

Key words: machine ethics, robot ethics, moral agent