The presence of a macroscopic interface between ceramic insulators and vacuum inevitably leads to multipactor under high electric fields, which is a significant threat to various electronic and electrical devices, as it is typically regarded as a precursor to electrical breakdown. In this study, we report a strategy using functionally graded lattice structures (FGLS) to manipulate the multipactor of the ceramic surface. First, particle-in-cell simulations were conducted to study the secondary electron avalanche process. Simulation results indicated that the interaction between electrons and FGLS hinders the development of secondary electron avalanche. Also, a few positive charges can be accumulated on the ceramic surface since FGLS eliminates the macroscopic interface between insulators and vacuum. Subsequently, stereolithography 3D printing technology was adopted to fabricate ceramic insulators with FGLS, and a further experimental characterization verifies the reduction of secondary electron yield, especially for surfaces with finer structures.