Matter-element model for city eco-security evaluation

Matter-element evaluation model for the ten cities eco-security in China was constructed by using of extension engineering method. Using this model, we can overcome the subjective one-sidedness in the multi-angle and multi factor identification evaluation. PCA was applied in the multi-index comprehensive identification. The following results were got in this article. Evaluation result of Nanjing city, Shenzhen city and Dalian city is relatively safe. Evaluation result of Shanghai city, Guangzhou city, Nanchang city and Hefei city is critically safe. Evaluation result of other cities is not safe. The results are basically interrelated to facts, so the model is feasible.