The micro-scale hemispherical resonator gyroscopes based on Micro-Electro-Mechanical Systems(MEMS) manufacturing technology are characterized by small size, light weight, low cost and suitable for volume production while absorbing the advantages of full-angle measurement of traditional hemispherical resonator gyroscopes. In the process of fabricating hemispherical shell structure by sacrificial layer process, whether the molds of hemispherical resonator on single crystal silicon have smooth surface and structural symmetry has decisive influence on the performance of hemispherical resonator. In this paper, the principle of isotropic etching of HNA(Hydrofluoric, Nitric, Acetic) for making micro-scale hemispherical resonator molds is described. Then the research progress of micro-scale hemispheric resonator gyro based on isotropic etching of HNA solution is introduced. Finally, the main technical problems of isotropic etching process are pointed out, and some possible solutions are put forward.