Abstarct: Because of its simplicity, the MIT bag model [1] is rather convenient for calculating various hadronic properties. The MIT bag model possesses many desirable feature inspired by QCD and relativity. Thus it is important to test the model in a situation other than those in which the dynamics of the model were originally formulated. The MIT bag model uses free quark wave-function with no-current boundary condition in the bag’s wall. Certainly, quarks interact within the bag, which will change the standard results. In the past, certain modification of the model was introduced, giving rise to better results compared to experimental values. In this paper, a modification is proposed by extending the model to include certain residual interaction among quarks. The relativistic wave-function is also taken. In our model, each quark moves inside the bag in the effective field of other quarks and gluons. the relativistic Dirac equation is considered with effective central potential for hadrons composed of three quarks as a three-body system and the ground-state wave-function and exited stats is calculated analytically . also thermodynamic properties of this system are studied . and in the end by determining the outward pressure forced via vacuum we will consider out side energy .