Shemshak Formation (Late Triassic-Lower Jurassic) in Iran is important because of the coal-bearing strata, In spite of the large number of research works on the coal basin of Alborz (Shemshak Formation) and Central Iran but there are few researches about the equivalent sediments in Isfahan region. The aim of this study was to examine hydrocarbon generation potential of hemshak formation in Soh area located in northeast of Isfahan by using Rock Eval pyrolysis and organic petrography. For this purpose, geochemical investigation of Shemshak formation as the source rock was carried out with 10 samples out of 20 samples were collected from the field area. In order to investigate the nature and distribution of the organic matters and the amount of content, 12 slides of selective samples ??prepared and were studied by microscope for petrography of organic matters. The results of Rock Eval pyrolysis indicate that all of examined samples containing of kerogen type 4, which is not suitable for generating hydrocarbon, although some of the samples like number 2 and 3 favor of a high level TOC that indicates the capability of generating hydrocarbon. Determining S1 and S2 parameters reflects a weak source rock which had formed by weathering and the type of organic materials. Based on petrographic microscopy , can be said that all of studied amples constitute of wooden and coaly organic materials which formed of inertinite maceral group. These macerals are weak in terms of generating hydrocarbon. Finally ,the results of Rock Eval pyrolysis and petrography of organic matters show that Shemsak formation having reached the metagenesis stage in Soh area.
