The invention relates to the field of biotechnology and medicine, in particular to two anti-HER2 antibody-chaetocin conjugates Trastuzumab-vc-Chaetocin (T-L-C) and Pertuzumab-vc-Chaetocin (P-L-C) and a synthesis and preparation method and application thereof. The conjugates are obtained through coupling medicine molecules with connecting groups with monoclonal antibodies. The structure is shown in the specification. The invention also provides the preparation method of the medicine molecules with connecting groups. The prepared antibody conjugates have the targeted effects on HER2 positive cells; lethality on HER2 positive tumor cells can be enhanced; the toxic and side effects generated by (+)-Chaetocin single medication can also be reduced; the huge potential treatment and application values are realized on cancer due to HER2 positive expression tumor cells. The formula is shown in the specification.