With complicated geological background, Putaohua reservoir in Sanzhao depression has lots of blocks. Based on its distribution characteristics and evaluation unit division as well as combined with detailed geological characteristics, parameters of developed and undeveloped blocks were optimized and the comprehensive evaluation parameters were determined. In order to make a correct evaluation for oil content, oil distribution, reservoir physical properties and productivity, this paper has adopted comprehensive quantitative evaluation method to do the comprehensive classification and evaluation for developed and undeveloped blocks. It can not only further improve oil recovery of developed blocks but also provide scientific basis for selecting favorable blocks for productivity construction of undeveloped blocks. According to the classification standard, the developed and undeveloped blocks of Putaohua reservoir in Sanzhao depression were separately divided into three types including Class Ⅰ, Ⅱand Ⅲ. In view of the geology and development factors, undeveloped blocks of Class Ⅰ are equivalent to developed blocks of Class Ⅱ; undeveloped blocks of Class Ⅱ are equivalent to developed blocks of Class Ⅲ; undeveloped blocks of Class Ⅲ are the poorest of all.