The study successfully processed GRACE data using de-correlation and 300km radius Gaussian smoothing and extracted the coseismic gravity changes caused by the 2010 Chile MwS. 8 earthquake. The peak to peak amplitude is 7μGal for gravity and the results agree well with that calculated using a dislocation theory for a spherical earth model. It is a new illustration of GRACE in detecting coseismic signals since it successfully detected the coseismic gravity changes caused by the 2004 Sumatra M9.3 earthquake. The result reported in this paper implies that GRACE is capable of detecting a coseismic signal caused by a magnitude M〈9.0 earthquake, and it is expected a wide application in studying seismic mechanism and other geophysical investigations.