Abstract: Frictional contact analysis is one of the most challenging problems in computational mechanics. The functional system of the contact problem is not only nonlinear, but also non-smooth, so in general the convergence and accuracy of contact algorithms are di cult to be guaranteed. For 2D elastic frictional contact problem, the scaled boundary isogeometric analysis combined with B di erential equation method (SBIGA-BDE method) is developed. Based on the scaled boundary isogeometric transformation, the contact equilibrium equation is derived by using virtual principle. The contact conditions are formulated as B di erential equation and satisfied rigorously. The convergence of the algorithm to solve the B di erential equation is guaranteed by the theory of mathematical programming. In the proposed method, only the outer boundary including the contact boundary need to be discretized isogeometrically, which reduces the spatial dimension by one and the boundary are represented accurately. The real contact length can be detected by the knot insertion algorithm. In addition, as the interpolatory functions used in geometry modeling and numerical analyzing are the same, the time costs in mesh generation is saved. The numerical examples, including Hertz contact problem and cantilever beams frictional contact problem, are presented and compared with analytic solution and ANSYS results. It validates the e ectiveness and accuracy of the proposed method in solving 2D elastic frictional contact problem.