Recently years, with something disturbed the stabilization of supply chain happened, supply chain risk assessment is getting more attention. Most of the past studies focused on an enterprise concrete risk, there were few systems analysis from supply chain network perspective. So, this paper builds enterprise importance assessment model based on multi-index optimal strategy firstly, according to the node location theory of complex network. This model can evaluate the comprehensive importance of an enterprise; Secondly, this paper brings the importance of evaluation results into supply chain network risk assessment model as a transition variable, and carries out inter-hierarchy assessment from microcosm risk of an enterprise to macrophysics risk of the supply chain network. At last, the empirical research shows that enterprise importance assessment model and supply chain network risk assessment model can make more accurate assessment result.