The invention relates to a 
data classification based data leakage prevention method and 
system, which can further improve the data leakage prevention effect. The 
data classification based data leakage prevention method comprises the steps as follows: A, designing a basic data classifier, B, defining various elements of DSL (domain specific languages) to form a data leakage strategy 
library, C, detecting input data via the DSL strategy 
library, executing defined response in the strategy, and writing time which violates the strategy into a data leakage event 
database, D, obtaining data, E, executing defined corresponding operation on the violated data, and F, performing 
statistical classification on the violated data leakage events, and displaying at a 
client. The 
data classification based data leakage prevention 
system comprises a basic classifier management module, a DSL strategy defining and editing module, a DSL 
strategy analysis execution module, a 
data access module, a data protection response module and an 
event management module.