为了解个体助人行为的发生、发展和变化，本研究采用质性研究方法，围绕日常生活中助人行为深度访谈了10名始成年期的高助人者，运用扎根理论对访谈资料进行分析和理论建构。发现个体助人行为的发展可分成三个阶段：形成期、冲击期及稳固期，各发展阶段以对助人行为的认知和主要动机为核心，呈现出稳定-外控、不稳定-外控、稳定-内控的特点，据此提出助人行为的发展历程，并讨论了研究的理论价值、现实意义及局限。

To explore how does individuals’ helping behavior develop after puberty, whether it change or not, what are the changes, and what are the influential factors during the process. This paper reviewed evolutionary explanation for the psychological mechanisms of prosocial behavior, theories and studies on development of children and adolescents’ helping behavior and its motivation. Few knowledges about the development of helping behavior in adulthood have been investigated. This study bridges the gap in prosocial behavior between social psychology and developmental psychology. In practical, it benefits our society through building a more altruistic environment. The present study used qualitative research method to collect and analyze data. Ten accommodating individuals in emerging adulthood, 4 females and 6 males, were semi-structured interviewed around their helping behavior in daily life. All interviews were recorded and transcribed into text, then coded and analyzed in NVivo 11 based on grounded theory. This format included data reduction and theme generation through using open coding, axis coding and selective coding sequently. The process of development of helping behavior emerged from the data, which can be divided into three stage. The first stage is the beginning and formation of helping behavior, which characterized by stable and external locus of control. At this stage people’s helping behavior was driven by inherent nature and social norm, but not personal will. They help for complying with the nature or conforming to the norms. As their growth and maturation, as well as the complexity of social environment and development of one’s cognitive abilities, they come to the second, sway stage. Its character showed in the name, which is still external locus of control but unstable. Because they realize that helping is neither a norm that everyone should comply with, nor must get good rewards. They became vacillate and doubt. Their action of helping was depended on external reward, such as reciprocation, affirmation, and good relationship. And the third stage is stabilization, featured by stable and internal locus of control. Through re-identifying with other helper, strengthening their early believes, or fulfilling inner deep needs (e.g. growth and achievement), helpers can restore cognitive coordination. Beliefs on helping behavior and their motivation varied at each stage. And developing path differ from person. Most interviewees were in the third stage after passing by the former two, some went straightly from the first to third stage, another was in the second stage. Then, the process of helping behavior development proposed in this study was compared with theories and findings in social psychology and developmental psychology. Our finding extends the development of prosocial behavior in developmental psychology to emerging adulthood. Manifested the vibration and stabilization after formation of helping behavior. Some suggestions were given for education and public media. Different strategies should be taken for different person. For children and adolescents, benefit of helping for others should be emphasized as usual. But for adult, we should offer some cases to help them find how to benefit themselves in helping. Finally, the limitations and future directions are analyzed.