Abstract: By comprehensive use of coring,casting thin section,scanning electron microscope,etc.,together with the logging data,the research on reservoir petrologic characteristics,pore structure characteristics and physical properties was carried out.Combined with the sedimentation and diagenesis research,the main controlling factors of tight sandstone were discussed.The research results indicated Yan-11 oil layers were mainly of quartz sandstone,feldspathic quartz sandstone and lithic quartz sandstone,the compositional maturity and textural maturity of sandstone were middle to high and the reservoir property was poor.The selectivity of sandstone was good,the initial porosity overall was high,about 38.8% on average.Due to the strong effects of rock components,74.2% primary pores were destructed and11.9% secondary pores were increased by the dissolution.Therefore,the diagenetic compaction and cementation are the main reasons of leading to tight sandstone of Yan-11 oil layers in Honghe oil field.