Macaronichnus segregatis in the Shahejie Formation of Paleogene in Chezhen Sag of Jiyang Depression is an intrastratal and irregularly meandering burrow structureIt is 7～8 mm in length and 1～3 mm in diameter，which is different in size from the same genus formerly discoveredThe ichnotaxon is commonly distinguished from several sedimentary environments：①places between channels of delta plain; ②delta，fan delta front bar and middle to outer fan of turbidite fan; ③shallow lake under humid climate；and ④shore to shallow lake sediments under periodically arid climateThey are generally found in silty mudstone deposited in different environmentsBased on the analyzed results of the hydrodynamic conditions,the chemical characters in different sedimentary environments and the forming process of Macaronichnus segregatis，some conclusions can be drawn as following: ① Msegregatis occurs in moderate water energy environments，and rather high or low water energy is not suitable for its existence；② The burrowmaker of Msegregatis lives among the upper dysoxic zone；③ Msegregatis is produced by depositfeeder before the substrate becomes firm，implied by the presence of linings surrounding the trace fossils