A new explicit time integration method was given for the solving of structural dynamic response. The proposed method was derived on the basis of uniform septuple B-spline interpolation approximation of nodal displacement, velocity and acceleration within any local time domain. The recursion formula of dynamic equilibrium equations was given as well as its computation procedure. Analysis shows, the proposed method can be unconditionally stable by selecting proper parameters. The numerical examples show, compared with the conventional Newmark method and Wilson-θ method, the proposed method possesses high calculation accuracy.