A model which enhances the integrity of BLP model was presented based on the BLP model.This model was called as EIBLP model.Some necessary restraints to upward information flow were appended in EIBLP without chang-ing the information flow direction（down-read and up-write） of BLP model and the security axiom

access labels of sub-ject and object

access control operation mode

and state transition policy of BLP model were improved.And then

ana-lyzes the security of EIBLP was analyzed and proved.It shows that the improved EIBLP model not only satisfies com-pletely the basic security of BLP

but also enhances the integrity of BLP with improving the upward restraints

the subject and object access labels

the model operation mode

and the model state translation rules.At the same time

the improved EIBLP raises the confidentiality of BLP at a certain extent.