To research the dynamics mechanism for knowledge acquisition via E-Learning of SNS oriented enterprise knowledge community in enterprise. Firstly, elements of knowledge acquisition via E-Learning of SNS oriented enterprise community were analyzed in- depth. Secondly, causal loop diagrams were made to make system analysis. Thirdly system dynamics model were established to describe development and changes of knowledge acquisition by modeling tools. Sensitivity analysis were made to explore the influences of parameters including, network size, E-Learning experience, knowledge demand and knowledge acquisition cost. By using system dynamics and sensitivity analysis, we can exploit the dynamic mechanism of knowledge acquisition via E-Learning of SNS oriented knowledge community in enterprise, so that strategy for knowledge community management can be proposed accordingly.