Background: There are few studies on the relationship between calcified plaques and stroke by ultrasound. We investigated the association between calcification in carotid plaque and stroke by analyzing the different characteristics of calcification and neovascularization distribution in heterogeneous plaques by both two-dimensional and contrast-enhanced ultrasound (CEUS). Methods: A total of 69 patients who were about to undergo carotid endarterectomy were selected between January 2016 and December 2017. Thirty-eight patients with cerebral ischemia were placed in the symptomatic group (amaurosis, TIA and no disability in the previous 6 months), and the other 31 patients, who were asymptomatic, were placed in the asymptomatic group. Two-dimensional ultrasound and CEUS were used to detect the calcification distribution characteristics and neovascularization in the plaques of all subjects. The differences of the calcification location, shape, quantity, and enhancement in the plaques were compared between the two groups. Results: There was no significant difference in calcification location between the two groups (P > 0.05). The symptomatic group had more nodular calcification but less strip calcification compared with the asymptomatic group (both P < 0.05). There was no significant difference in mixed morphologic calcification between the two groups (P > 0.05). The symptomatic group had a higher calcification quantity (P < 0.05). The symptomatic group exhibited more fibrous cap fracture and intra-plaque hemorrhage in H&E staining (chi(2) = 17.133, P < 0.001, chi(2) = 10.003, P = 0.003) and higher CD31 expression (t = 7.584, P = 0.000). Conclusions: The quantity and shape of the calcification, and the presence of neovascularization adjacent to the calcification have certain effects on the stability of plaques. Multiple calcifications, nodular calcification, and neovascularization near calcification may cause plaque rupture and therefore might be risk factors for stroke. Our results suggest that the joint use of two-dimensional ultrasound and CEUS can provide comprehensive information on plaques to assess their stability.