Abstract: In this paper, optimal identical designs of bivariatepanel data model based on within estimator are discussed. It is proved that D-, A-, E- and I-optimal design of bivariate panel data model can be obtained on the vertexes of the design region. Equal-weight design is proved to be D-,A-, E-optimal of bivariate panel data model in the paper. I-optimal design is also obtained in the paper and it shows that equal-weight design has high I-efficiency.