In this paper, a new method of the laser etching technology was proposed for the small adjusting parameter of the microwave dielectric ceramics resonator. The FEM for solving the eigenvalue problem was firstly deduced by electromagnetic theory, meanwhile, the shortcomings of the mechanical adjustment resonator parameter was verified with the FEM. Several factors affecting laser etching operation were mainly explored. The relationship between laser etching parameters and resonant frequency variation was obtained through experiments. Finally, the advantage of laser etching technology was verified with self made dielectric resonator, which its relative frequency error was less than 0.2%.