中文摘要：

不同规模的城市通常平均工资水平不同，这可能源于能力群分、生活成本差异或者城市集聚经济效应。本文利用全国2008届大学毕业生求职与工作能力抽样调查数据，实证考察不同规模城市的工资差异并检验多种理论假说。我们发现，各种假说均能不同程度地解释直辖市与副省级城市相对于地级城市的工资溢价，但城市集聚经济假说最为重要，其次是生活成本差异，这与发达国家能力群分和集聚效应明显的经验事实相区别。稳健性检验进一步支持分析结果。

英文摘要：

Cities with different size usually have different wage levels, which may stems from ability sorting, living cost differences, or urban agglomeration economy. Using a survey data of Placement and Ability of Chinese College Graduates graduated in 2008, this paper empirically analyzes the wage differentials between different levels of cities, and tests the reasons for that. We find that, the above hypotheses can, to different degrees, explain the wage premia in municipalities and sub -provincial cities compared to prefectures, especially the agglomeration economy and the living cost difference, which is different from the facts that ability sorting and urban agglomeration effects are important in developed counties. The robustness checks further support the above arguments.