Abstract: Objective To satisfy the need of clinic diagnosis, a rapid samples preparation method of rat tissues for TEM observation by microwave process is investigated. Methods The samples of from viscera were divided into three groups numbered Ml, M2 and M3 according to the difference in processing time and microwave power. Results The ultrastructures of the cells can be preserved intactly as original state and a clear ultrastructure and boundary can be observed in all groups. For M2 group, no evident ultrastructural difference can be seen between processed samples and normal samples. But for other groups, slight swelling of mitochondrion from liver and heart in M1 group and slight scathe from organoid of liver, kidney and heart in group M3 were found. Conclusion The preparation time of electron microscope samples can be greatly shorteneed by microwave process on the premise of intactly preserving ultrastructures of viscera cells, therefore shorten the diagnosis time in clinic.