中文摘要：

当前，国内特大城市纷纷采取多中心空间发展战略来缓解单中心集聚带来的城市病，然而在实践中次中心往往难以形成，因而明晰就业次中心的形成机制对于多中心城市结构建设具有重要意义。现以上海都市区为例，运用logistic回归模型探讨其就业次中心的形成机制，并与北京都市区研究结果进行了比较。结果发现，丰富的劳动力要素与交通基础设施对于上海和北京就业次中心的形成具有重要作用；人力资本与距高速公路距离对上海都市区就业次中心形成也具有正面影响；主、次中心的空间相对位置和经济结构因素也显著影响次中心的形成。但北京和上海具体表现有所不同，北京就业次中心倾向于靠近主中心分布，服务业增长较快的空间单元更有可能发展成为就业次中心；而上海就业次中心倾向于远离主中心分布，制造业和服务业发展均对就业次中心形成具有显著影响。此外，政策对于北京、上海就业次中心的形成具有一定促进作用，但效应并不如预期明显。

英文摘要：

The polycentric spatial strategy has been applied in many Chinese mega cities recently, but has seldom yielded any expected effects. Empirical re- searches aiming at demonstrating the spatial distribution of employment have made great progress in methodology, however, understandings about the mecha- nism of the formation of employment subcenters and the decisive factors in the process remain vague and fuzzy, which is demonstrated by some of the studies to have a strong connection with the performance of the strategy This research inves- tigates the determinants of the emergence of employment subcenters in the Shang- hai metropolitan area based on a binary logistic model with street-block data The outcomes are compared with that from studies on the Beijing metropolitan area. It is found that the former agglomeration of labor forces and transportation infra- structures have a significant impact on the development of employment subcenters in both Beijing and Shanghai, which means agglomeration economy still plays a role in the formation of employment subcenters. Findings also suggest that the proportion of labors with a higher educational background and the proximity to highway are positively related to the formation of employment subcenters in Shanghai. Besides, the spatial and economic structures of the city also play an im- portant role in the formation of subcenters. There are some differences between Beijing and Shanghai. In Beijing, it is found that the probability of the emer- gence of employment subcenters decreases significantly with the increase of dis- tance to the main center and the development of service industries helps to pro- mote the subcenters. In Shanghai, however, employment subcenters tend to locate away from the central area, at the same time, both manufacturing and service in- dustries can raise the probability of the emergence of employment subcenters. Ur- ban planning and the construction of state-level development zones have some pos- itive impacts on the formation of subcenters, but not i