The interactive behavior of organisms within social systems often extends across multiple communities and plays a crucial role in the evolution of the systems. By constructing a finite population-based evolutionary game model, we explore the evolutionary dynamics of cooperative behavior when multiple communities interact jointly. Specifically, increased dilemma strength within community is linked to a noticeable reduction in the Cooperation frequency. Weaking inter-community dilemma intensity, particularly under low selection intensity, acts as a deterrent rather than a cooperative catalyst. Additionally, intra-community environmental fluctuations impact community size dynamics. Weaker selection supports cooperative behavior and increases community size variation, while robust selection poses challenges to altruism, resulting in minimal community size changes. Overall, this study deepens the understanding of multicommunity interactions and reveals some counterintuitive phenomena in the context of complex behavioral patterns, which further underscores the need to explore the common interactions of multiple social groups.