On the basis of gravity observation data from 2010 to 2013 in the Sichuan area，we draw dynamic pictures of gravity field and curves of gravity segment difference at some measuringsections． These pictures have been used to study the dynamic evolution characteristics of the gravity field before and after the Lushan MS7． 0 earthquake． The result shows that the gravity field has experienced increase change about 3 years and decreases change about 1 year before the earthquake in a gravity field variation pattern of rise→accelerated rise→slow rise→accelerated decline→slow decline． The Lushan earthquake occurred in the callback procedure of the gravity field from decline to increase． The gravity field changes returned to near pre-earthquake conditions at a faster rate after the earthquake with the anomalies in positive gravity change areas． The gravity field changes of epicenter region was smaller before the earthquake and the tectonic activities were slower．