Thick Cambrian dolostone strata are distributed in Tarim basin. The petrology analysis of the drilled cores from the rock shows that the Cambrian dolostone can be divided into six types of genesis: tidal flat sedimentary dolostone (TSD), lagoon sedimentary dolostone (LSD), permeability-reflux secondary dolostone (PRSD), campacting fluid secondary dolostone (CFSD), secondary dolostone crystallized in burial karstification under low temperature (BKLTSD), and hydrothermal fluid secondary dolostone (HFSD). Based on the analysis of physical property from the cores and thin sections, it is shown that BKLTSD could be the best high-porous and high-permeable reservoir, TSD and HFSD could be high-porous and low-permeable reservoir and the others could not be good reservoirs in Tarim basin.