Abstract: On the basis of the overview of status and problems of Feixianguan Formation dolomitite origin in the Northeastern
Sichuan Province，through the study of the micrite-microcrystalline dolomite and fine grain-microtek dolomite’s petrological
features，degree of order characteristics，cathodoluminescence characteristics，isotopic，and the diagenetic fluid temperature，
paleosalinity：we think that dolomitization of rocks formed by the microcrystalline dolomite，such as micrite- microcrystalline
dolomitite，algal-laminated dolomitite，etc.，are Quasi-syngenetic dolomitization，but dolomitization of rocks mainly composed
of the fine grain-microtek dolomite，like crystalline dolomitite，oolitic dolomitite，etc.，are formed by burial dolomitization，
The analysis of the distribution features of strontium isotope we come to the conclusion that the burial dolomitization occurred
in a closed system.

Key words: burial dolomitization, dolomite, origin, Feixianguan Formation, northeastern Sichuan Basin