Based on Thompson and Barraclough magnetic field models and the eighth generation of International Reference Field (IGRF), the main parameters of main magnetic field for the dipole magnetic field, the non-dipole magnetic field, westward drift and geomagnetic spatial power spectrum were calculated and analyzed. The secular variations of each parameter were analyzed. The magnetic moment of magnetic dipole has been connectively decreasing since 1600. Magnetic center has departed the Earth's center quickly and moved 291km toward northern Pacific since 1800. There is an approximate-30-years periodicity for westward drift. The distribution range is very large, and the intensities are very strong, and the changes are connective for the following 3 non-dipole magnetic anomaly since 1600: Southern Atlantic positive anomaly, African negative anomaly and oceania negative anomaly. Eastern Asian positive anomaly and Northern American positive anomaly are non-dipole magnetic anomaly formed gradually after 1700. There is a very strong positive anomaly in the Northern Pacific during the 17th century.  