The relationship between phenomenological psychology and transcendental phenomenology is regarded by Husserl as parallel and overlapping. It is neither a clear thought, nor has been solved properly by the development of phenomenology, but justified in the practical field of apply sciences. How does it happen? What is it meant? In this paper, we point out the solution by considering the phenomenological psychology as a qualitative research through the distinction between descriptive ethics and situation ethics, which is in between meta-ethics and normative ethics. That is to say, phenomenological psychology shows itself to us due to situation ethics, while situation ethics regains its ontological sense due to phenomenological psychology.