The Oxidation of aflatoxin $G_1$ ($AFG_1$) with ozone in chloroform solvent gave the stable ozonide into ozonization of the double bond in the terminal furan ring, and this reaction have been carried out for 3hr at -78. 5$^{circ}C$. The chloroform solvent was removed in a stream of nitrogen and the residue was separated by elution chromatography(EC). The structure of this compound have been identified by using MS, $^1H-NMR$, $^l3C-NMR$ and I. R spectroscopy, respectively. This compound was formed the normal stable AFG$_1$-ozonide into spontaneous rearrangement after unstable ozonide according to sigmatropic rearrange ment dependent upon cyclo addition by ozone.