Objective:To assess the virtual touth quantification(VTQ) in evaluating the efficacy of neoadjuvant cheomotherapy(NAC) on breast cancer. Methods:Thirty-one clinical stage II-III breast cancer patients were enrolled in the study which underwent neoadjuvant cheomotherapy.All patients underwent traditional ultrasound,VTQ and pathologic evaluations.the response evaluation criteria in solid tumors(RECIST 1.1)were used to evaluate the traditional ultrasonic efficacy.Then,VTQ were underwent before and after NAC.The ultrasonic evalating criteria were the tumor size reduction rate,the VTQ value of the tumor center(VTQcenter),the VTQ value of the tumor margin(VTQmargin),the VTQ Ratio of tumor center to fat(VTQRcenter/fat), the VTQ Ratio of margin to fat (VTQRmargin/fat).The response of NAC was defined as effective(CR+PR)if the reduction rate of VTQ value≥30％；stable disease(SD) if the reduction rate of VTQ value value<30％；progressive disease(PD) if VTQ value value increase．The Miller-Payne grading system was used to evaluate the pathologic response;CR+PR correlated with major pathologic response(MHR= G4+G5)；SD+PD correlated with non major pathologic response(NMHR=G1+G2+ G3)．Then,the multiple regression analysis were used to analyse the influence factor of NAC efficacy; the paired t-test were used to compare the VTQ value pre-NAC and post-NAC;the t-test were used to analyze the tumor size and VQT value reduction rate after NAC between the MHR and NMHR groups;The agreement of NAC response between traditional ultrasound,VTQ and hispathological results was measured using Kappa statistics. At last,the efficacy of tumor size,the VTQ value reduction rate and the combination in the evaluation of NAC were compared by ROC analysis. Results:1.the multiple regression analysis found that the age and the tumor center VTQ value before and after NAC were the independent predictors.2.Compared with the pre-NAC value,the VTQcenter,VTQmargin,VTQRcenter/fat,VTQRmargin/fat and the tumor size after NAC had statistical significance(the P value were 0.000,0.000,0.012,0.000,0.000 respectively).3.After NAC,the VTQcenter,VTQmargin,VTQRcenter/fat,VTQRmargin/fat between the MHR and NMHR groups had statistical significance(the P value were 0.000,0.001,0.013,0.038 respectively).4.The agreement between tumor size reduction rate,the reduction rate of VTQcenter,VTQmargin with Miller-Payne grading system were 0.322,0.695,0.563 respectively(P<0.05).5.The area under the ROC curve of tumor size reduction rate,the reduction rate of VTQ value and the combination of both were 0.655,0.905,0.909（center）and 0.655,0.734,0.756(margin) respectively(P<0.05) in the evaluation of the NAC efficacy. Conclusion :The VTQ value differences is an effective method to assess the efficacy of NAC.The accuracy of measuring the tumor size is relatively low;combined with the VTQ technique,the efficacy can be effectively improved.