Many MEMS devices including accelerometer and gyroscopes, having moving parts, requires hermetic and low cost packaging. In this paper we propose a low cost fabricating process to prepare micro glass cavity arrays for wafer-level and hermetic packaging of MEMS. First, the fundamental of the process was discussed. Then, the process for preparing cavity arrays in Pyrex7740 glass wafer was studied experimentally. After that, the defects of the fabrication were discussed. Results show that wafer-level packaged cavities were prepared, whose diameter was controllably between 200 microns and 2000 microns. It is also disclosed that the defects could be avoided by controlling the process parameters. Results also show that the leakage rate of the single packaged cavities is below 5Χ10-9 Pa.m/s which could meet the hermetic packaging standard.