Abstract: From Lower to upper，Aoxi Formation is divided into 3 lithologic Member at Shizhu-Yaxi，Tongren area，Guizhou Province. The MemberⅠof Aoxi Formation is dominated by muddy dolomite and fine dolostone and yields a number of trilobite fossils，including Probowmania（Mufushania）nankingensis、Probowmania（Pr.） balangensis、Balangcunaspis（B.）transversu、Oryctocephalops sp.、Kootenia sp. and Deiradonyx tongrenensis sp.nov..Among Deiradonyx is occurred in the Alexandria beds of lower Templetonian in Australia，Oryctocephalops is from the lower part of Amginian in Siberia and their age is early Cambrian. Kootenia is appeared often from Tsinghsuting Fromation of Lower Cambrian，Other trilobites are common components in the lower part of Kali Formation. Above discovery of trilobites has changed the era of Aoxi Formation. This Formation is an age-straddling lithostratigraphic unit and be disintegrated in the lower and middle Cambrian stratigraphic units. The upper part of MemberⅠfrom Aoxi Formation should be assigned to top of Lower Cambrian， and this part and its proximate shale containing kalium part of Member Ⅱ composed Kaili Formation together in the section