Aim To assess the biomechanical characteristics of carotid isolated plaques using intima-media thickness (IMT) automatic tracking technique. Methods The study included 30 patients who had isolated plaques in carotid artery. IMT strain rate (SR), IMT time strain rate (TR) and AIIc% were measured by IMT automatic tracking technique along with acoustic densitometry (AD) to assess the variation of the IMT and acoustic density in the upstream, fibrous cap top and downstream regions of the plaque and ipsilateral normal carotid. All plaques were divided into three groups according to IMT:small group (1.2 mm2.5 mm). The differences of SR, TR and AIIc% were identified among three groups. Results SR and TR were significantly reduced in plaques group compared with controls. Compared with cap top area(CTA), the SR of upstream area (UA) were significantly increased. However, the SR, TR of downstream area (DA) were significantly lower than CTA and UA. Compared with control, the SR, TR were significantly reduced in CTA and DA. AIIc% in UA and CTA were significantly lower than DA. AIIc% in all three regions were significantly higher than that in control group. The SR, TR for the 3 plaque regions were negatively correlated with AIIc% (r=－0.63, r=－0.58, P<0.05). The SR, TR among three groups showed no statistical significance. Conclusion IMT automatic tracking along with AD could be applied to identify the anisotropic biomechanical features in carotid isolated plaques, which may be a new noninvasive way to early assess the biomechanical properties of carotid plaque.