A new molecular structural characterization(MSC)method called molecular vertexes correlative index(MVCI)was constructed in this paper.The index was used to describe the structures of 45 compounds and a quantitative structure-activity relationship(QSAR)model of toxicity(–lgEC50)was obtained through multiple linear regression(MLR)and stepwise multiple regression(SMR).The correlation coefficient(R)of the model was 0.912,and the standard deviation(SD)of the model was 0.525.The estimation stability and prediction ability of the model were strictly analyzed by both internal and external validations.The Leave-One-Out(LOO)Cross-Validation(CV)correlation coefficient(RCV)was 0.816 and the standard deviation(SDCV)was 0.739,respectively.For the external validation,the correlation coefficient(Rtest)was 0.905 and the standard deviation(SDtest)was 0.520,respectively.The results showed that the index was superior in molecular structural representation.The stability and predictability of the model were good. A new molecular structural characterization (MSC) method called molecular vertexes correlative index (MVCI) was constructed in this paper. The index was used to describe the structures of 45 compounds and a quantitative structure-activity relationship (QSAR) model of toxicity (-lgEC50 The correlation coefficient (R) of the model was 0.912, and the standard deviation (SD) of the model was 0.525. The estimation stability and prediction ability of the model were completely analyzed by both internal and external validations. Leave-One-Out (LOO) Cross-Validation (CV) correlation coefficient (RCV) was 0.816 and the standard deviation (SDCV) was 0.739, respectively. For the external validation , the correlation coefficient (Rtest) was 0.905 and the standard deviation (SDtest) was 0.520, respectively. The results showed that the index was superior in molecular structural representation. stability and predictability of the model we re good.