Meaning in life is an ongoing theme because the human pursue meaning in life across their whole life. The human request for their own unique sense of meaning links to their efforts to cope with their anxiety for the unavoidable death. Meaning in life is extracted from the individuals' understanding of themselves, their environment and their relationships with the environment, which mainly involve self-concept and relationship. To clarify self-concept and improve relationship are the key and useful methods to construct human's sense of meaning in life. Self-concept includes the cognitive component regarding who I am and the evaluation component regarding how I feel about myself. It focuses on the content and organization of self-knowledge. A stable and clear self-concept enables individuals to understand themselves, the world and relatedness to the world more accurately, and to understand their life experiences from the perspectives of a long-term goal and a higher level, and then to grasp the meaning which is hided in various life events. Also, relationship is an important factor which affect meaning in life. In essence, meaning is relational and the mental representation of various relations among things. And during the interaction with the world, individuals acquire sense of self and sense of confirmation, so as to construct their self-concept. Individuals establish their self-concepts by getting feedbacks from relationships. By comparing these feedbacks, individuals can answer the fundamental questions about who they are. In sum, relationship will influence the construction of meaning in life by influencing their self-perception and evaluation, that is, self-concept. In order to explore the effects of relationship and self-concept on meaning in life, and test the role of self-concept in the association of relationship and meaning in life, the present study surveyed 1087 students from three colleges for twice during a year, using the Wallace Self Concept Scale(WSCS), the Balanced Measure of Psychological Needs Scale(BMPN), and the Presence of Meaning subscale in Meaning in Life Questionnaire(MLQ-P). Results show that (1) there is a positive correlation of simultaneity and succession among relationship, self-concept and meaning in life; (2) relationship, self-concept and meaning in life can predict with each other at both Time 1 and Time 2; (3) and most importantly, both of relationship and self-concept are the antecedents of meaning in life, as well as self-concept serving as a mediator in the association of relationship and meaning in life. In other words, relationship affected meaning in life via self-concept in college students. These findings suggest that the sense of meaning in life will be improved by the improvement of relationship and self-concept. That is, to actively participate in social interactions with a self-affirming heart.