Objective:To explore the significance of enthesitis in psoriasis(PsO) and the value of high-frequency Doppler ultrasound (HDUS) in screening potential subclinical psoriatic arthritis(PsA) patients through enthesitis; Designing the semi-quantitative score of enthesitis explore the value of semi-quantitative score in evaluating the degree of joint structure damage and improving the curative effect in patients with subclinical PsA.Methods:Clinical and sonographic data were collected in 125 PsO patients and 50 osteoarthritis (OA) patients who attended hospital from January 2019 to March 2021, and healthy controls (HC) recruited during the same period. The prevalence of enthesitis of distal interphalangeal joint (DIP) of psoriasis patients, osteoarthritis patients and HC was compared. Meanwhile the semi-quantitative scoring system for ultrasound-guided enthesitis was designed, and the correlation between the severity of enthesitis and clinical score was analyzed. The correlation between psoriasis nail and enthesitis of extensor tendon of DIP finger was also analyzed.Results:The significant difference was found in the prevalence of enthesitis of DIP among PsO group, OA group and HC group (all P<0.001); There was a significant difference in the severity of enthesitis of DIP in PsO group before and after treatment ( P<0.001); In PsO group, the correlation between the severity of enthesitis of DIP and Psoriasis Area and Severity Index(PASI)score was moderate ( rs=0.538, P<0.001), and highly correlated with Nail Psoriasis Severity Index (NAPSI) scores( rs=0.877, P<0.001). There was a significant difference in the incidence of enthesitis between the patients with psoriasis nail and the patients without that ( P<0.001). The prevalance of enthesitis of nail disease free fingers was also found significantly different between PsO group and HC group( P<0.001). Conclusions:Enthesitis is a prominent characteristic of PsO.And the semi-quantitative scores designed in this research are in satisfied consistence with the clinical scores, and could be used to evaluate subclinical PsA structural damage.Furthermore, it is possible that the enthesitis of DIP is a relatively independent process from the nail disease.