This paper aimed at exploring motivations for participation in virtual community and virtual world. An interpersonal relationship perspective was introduced as a framework to explore this participation behavior using an interpersonal relationship model—the Fundamental Interpersonal Relationship Orientation (FIRO) model (Will C. Schutz, 1958; William Carl Schutz, 1966). Specifically, the paper attempted to demonstrate that members’ virtual behavior was a response of them to fulfill their interpersonal relationship needs. Two types of their virtual involvement behavior -- Behavior to Obtain Information (BOI) and Behavior to Give Information (BGI) – were investigated in our research. Data used in our analysis was collected from a virtual community—Microsoft Chinese Community and a virtual world—Cyworld. Our ANOVA results suggested that interpersonal relationship model was an applicable construct to explain virtual behavior.