Abstract: In this paper a brief introduction has been given to the definition and main features of the common geodetic coordinate system at home and abroad, the differences and similarities between them have been discussed, and application results of geodetic coordinate system in the field of off shore petroleum exploration are finally presented.There is minimal error between WGS84 coordinate and CGCS2000 coordinate, which can be used both in oil and gas exploration.WGS84 will still remain the main coordinate system used in petroleum exploration.