The highly dynamic attachment and detachment of insects involve impressive frictional phenomena that manifest as strong friction with weak pull-off force during high-speed movements. Here, we design and fabricate biomimetic pad (BP) inspired by the external and internal cuticles of the euplantulae of insects. A mechanical analysis of the BP reveals that the contact surface consistently exhibits a hemispherical shape with an even curvature, and its internal structure consists of a uniform pillar array. Furthermore, a suitable structural ratio is identified by comparing the frictional performances of BPs with different structural parameters. The high frictional attachment of BP with optimized structure is a result of the combined effect of large actual contact area and high structural stiffness.