Abstract: Study on the hydrocarbon source rocks of Lower- Palaeozoic in North China is very important to the Pre- Tertiary oil-gas strategic precinct.From the point of view of sedimentology,the types,quality evaluation and genesis in the study area are analyzed according to the sta- tistics of parameters of TOC(%),hydrocarbon genera- tion potential and chloroform bitumen'A'.The results in- dicate that preferable hydrocarbon source rocks are found to be existed in the Lower-Majiagou formation,the Up- per-Majiagou formation and the Fengfeng formation of Ordovician.The necessary factor of the source rock devel- opment is the productivity of marine organisms,while the main factors are paleoclimate,palaeosedimentary environ- ment,palaeostructure and sedimentary process.These re- sults can provide a lot of effective geological information for the Pre-Tertiary oil-gas strategic precinct in the East of North China.