Objective This study aimed to investigate the relationship between alkaline phosphatase (ALP) and common carotid intima media thickness (IMT), carotid plaque, and extracranial carotid artery stenosis (ECAS). Methods A total of 3,237 participants aged >= 40 years were recruited from Jidong community in 2013-2014. Participants were divided into five quintile groups based on their serum ALP levels. Carotid atherosclerosis was assessed using ultrasound. Abnormal IMT, carotid plaque, and ECAS were defined as IMT > 0.9 mm, IMT > 1.5 mm, and >= 50% stenosis in at least one extracranial carotid artery, respectively. Results Common carotid IMT values and the prevalence of carotid plaque increased across serum ALP quintiles. Higher ALP quintiles were correlated with an increased risk of abnormal IMT [fourth quintile: odds ratio (OR) 1.78, 95% confidence interval (CI) 1.13-2.82, P = 0.0135; fifth quintile: OR = 1.82, 95% CI: 1.15-2.87, P = 0.0110] and ECAS compared to the lowest quintile (fifth quintile: OR = 1.47, 95% CI: 1.09-1.97, P = 0.0106). The association between ALP and prevalence of carotid plaque became insignificant after adjustment for confounders. Conclusion Serum ALP levels were independently associated with abnormal common carotid IMT and ECAS. These conclusions need to be further corroborated in future prospective cohort studies.