This floristic study were conducted in Kakareza forest in Lorestan province. Kakareza forest is located in 45 km far from eastern north of Khoramabad city. The study area elevation varies from 1600 to 2800 m ASL. Flora of this forest was identified by floristic method and then biological forms and plants chorotype were identified. Conservatism coefficient of plant species were assigned for the first time in Iran. In this forest 194 plant species were identified and the important families are, Fabaceae(36), Asteraceae(24), Poaceae(19), Brassicaceae(16) and Apiaceae(15) respectively . Chief biological forms are Therophytes 63.9%, Geophytes 20.21 %, hemichryptophytes 12.56% and Chamophytes 3.27 %. Investigation on chorology of plant species showed that 48.91% of species belong to Irano_Touranian- Medditerian region and other species can be found in other regions too. Results indicated that 56.18% of species belonging to first category of conservatism coefficient scores (1-3) and only 1.58% of species have the highest conservatism coefficient (9-10). Presence of many species in this region shows that this area has suitable richness; therefore we can judge that this region has high heterogeneity. Identification of conservatism coefficient can be a complementary index for next studies too.