To explore the dynamics mechanism for knowledge acquisition via E-Learning of SNS (Social Network Service) knowledge community in enterprise, so that strategy forknowledge community management can be proposed accordingly. Firstly, elements of knowledge acquisition via E-Learning in knowledge community are analyzed. Secondly,causal loop diagrams are made to make system analysis. Thirdly system dynamics model is established to describe development and changes of knowledge acquisition bysystem dynamics modeling tools. Then sensitivity analysis is made to explore the influences of parameters including, network size, E-Learning experience, knowledgedemand and knowledge acquisition cost. By using system dynamics and sensitivity analysis, we can exploit the dynamic mechanism of knowledge acquisition via E-Learningof SNS oriented knowledge community in enterprise.