In this article, a novel set-membership state estimation method based on zonotopes is proposed for switched systems subject to unknown-but-bounded disturbance with average dwell time (ADT) switching. By testing the consistency between the system model and measured output, an intersection zonotope is constructed based on mode-dependent and semitime-dependent correction matrix. Then, by constructing semitime-dependent <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$P$</tex-math></inline-formula> -radius functions, the issue of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$L_{\infty }$</tex-math></inline-formula> disturbance attenuation performance for the intersection zonotope is addressed. Finally, a numerical example is presented to illustrate the effectiveness of the proposed approach.