由交易平台、店家和顾客构成的电子商务内部生态的平衡，是C2C类电商企业可持续发展的根本保障。在生态平衡的电商平台上，1) 店家无论大小老嫩，无论经营的是大路货还是小众品，只要它能满足顾客的需要，就有生存空间；2) 能在店家和顾客之间实现精准的供需匹配，满足消费者的个性化需求。 商品目录，即商品分类体系通过公平的流量分配、精准的导购来实现电商平台的生态平衡。当前的商品分类体系，沿袭了等级分类法以信息组织为中心目标的构建模式，难以满足在多样化的商品市场上公平导购、面对个性化的用户需求精准营销的需求。本课题提出：1) 在全局层面，构建多维动态商品分类体系，使其类目结构与市场上商品的生态分布同构，并通过类目自动更新机制及时反映商品市场的变化；2) 在局部层面，为每个用户构建个性化的目录空间，推荐用户感兴趣的类目和产品，作为商品发现机制的补充手段，实现精准的供需匹配。

The ecological balance of the core layer of e-commerce, which is composed of the online trading platform, sellers and buyers, is the fundamental guarantee for sustainable development of C2C e-commerce enterprises. On an ecologically balanced e-commerce platform: 1) No matter a seller is old or new, and no matter what it sells are popular or for the minority, it can have its own living space and market opportunities as long as it can satisfy some customers' needs; 2) There is a precise matching between a specific seller and its corresponding buyer, so that customers' personalized needs can be satisfied. Product catalog, or product taxonomy, achieves the ecological balance of e-commerce platform by fair flow distribution and precise shopping guide. Current product taxonomy follows the traditional enumerative classification which uses an architectural pattern centered on information organization, thus has great difficulty in achieve fair shopping guide in a diversified commodity market and realizing precision marketing based on personal needs. The purposes of this research are: 1) to construct a multi-dimensional dynamic product taxonomy for the overall platform, making the catalog consistent with the ecological distribution of all commodities, and show the change of commodity market in time by an automatic update mechanism of the taxonomy and catalog; 2) to construct a personalized catalog space for each customer to recommend his or her interested catalog and products, thus supplementing current mechanism for finding product and promoting the precise matching between suppliers and customers.