Keywords: 
• planktonic algae /
• benthic algae /
• kinetics /
• element

Abstract: Hydrocarbon generation kinetics simulation was carried out to planktonnic algae and benthic algae , with the thermal simulation and element composition analysis ,the results show that planktonic algae and benthic algae are characterized by high abundance of N,S,O atoms and low hydrocarbon activation energy .Average activation energy is about 220 kJ/mol; and the activation energy of the beginning of hydrocarbon generation is less than 184 kJ/mol; the activation energy is respectively 251 kJ/mol and 255 kJ/mol to reach 90% hydrocarbon generation ratio; and generate great abundance of hydrocarbon when they are still immature. However, the period of hydrocarbon generation of planktonnic algae and benthic algae is very long ,the span of activation energy in the period of 10% to 90% kerogen transformation ratio are respectively 59 kJ/mol and 71 kJ/mol; the span of temperature are respectively 166.8 ℃and 201.2 ℃. The planktonnic algae would generate hydrocarbon much more quickly than benthic algae, the carbon conversion ratio of hydrocarbon generation of planktonic algae and benthic algae is respectively 61.77% and 34.9%.The products of hydrocarbon generation are main asphaltene and resin. Planktonnic algae and benthic algae are the main source of immature and lowmature oil.