本文以山东省为例,把个人所得税收入能力分为现实收入能力和潜在收入能力两个层面。山东省个人所得税现实收入能力较全国平均水平为低,更远远低于国际水平。而从潜在收入能力来看,山东省个人所得税潜在收入能力巨大,但转化能力不足,税收流失率从2000年的37.75%增加到2007年的58.70%。究其根源,信息不对称、征管权与收入归属权不匹配、纳税人遵从率低和税制的低效等是造成这一现象的主要原因。 In this paper, Shandong Province as an example, the individual income tax income ability is divided into real income ability and potential income capacity of two levels. Shandong Province, personal income tax income than the real income capacity of the national average is low, much lower than the international level. However, from the perspective of potential income, the personal income tax in Shandong Province has huge potential income but insufficient conversion capacity. The tax loss rate increased from 37.75% in 2000 to 58.70% in 2007. The main reason for this phenomenon is its root causes, asymmetric information, mismatch of tax collection right and income ownership, low compliance rate of taxpayers and inefficiency of tax system.