The article analyzes the chaotic dynamic characteristic of geomagnetic variation field mainly in two aspects: (1) analyzing the chaotic dynamic characteristic of the geomagnetic variation field data observed at the same period (both low geomagnetic disturbance period and high geomagnetic disturbance period) from a series of geomagnetic stations using multiple approaches, in order to get a sufficient proof to validate whether there is chaotic dynamic characteristic in geomagnetic variation field; (2) analyzing the chaotic dynamic characteristic of the geomagnetic variation field data observed at different periods from the same geomagnetic station, aiming at finding out whether there is a parameter-varying chaotic characteristic in the geomagnetic variation field. The results indicate: (1) There is definitely chaotic dynamic characteristic in the geomagnetic variation field time series. (2) In view of chaotic time series phase space reconstruction, the number of independent variables to simulate the geomagnetic variation field dynamical system is about 6. (3) Geomagnetic variation field time series shows not only chaotic dynamic characteristic but also parameter-varying dynamical chaotic characteristic.