Ulcerative colitis (UC) is a chronic inflammatory bowel disease with rising global prevalence.Histological healing (HH) is a key treatment target associated with better long-term outcomes. Although endoscopic ultrasound (EUS) is known to be related to both clinical and endoscopic activity in UC, its role in defining HH remains unclear. Therefore, this study was aimed at investigating the association between EUS and histological activity (HA), as well as the predictive potential of EUS for HH. In this cross-sectional analysis, 68 UC adults underwent EUS and colonoscopy with biopsies. We used the Mayo Endoscopic Score (MES) for endoscopic activity, the Nancy Index (NI) for biopsy grading, and the Endoscopic Ultrasound-Ulcerative Colitis (EUS-UC) score for EUS analysis, defining endoscopic remission as MES ≤ 1 and HH as NI ≤ 1.A receiver operating characteristic (ROC) curve was employed to evaluate the ability of the indices to predict HH. Totally 23 patients (33.80%) achieved HH, while 45 (66.20%) showed HA. The EUS-UC scores were significantly lower in the HH group (p < 0.001) and correlated strongly with NI (ρ = 0.73). EUS-UC score was an independent risk factor for HH (adjusted OR = 1.918, 95% CI: 1.195-3.080, p = 0.007). The EUS-UC score demonstrated a strong predictive value for HH, with an AUC of 0.840, a sensitivity of 75.56%, and a specificity of 78.26%. The EUS-UC score has a significant correlation with histological outcomes and shows strong potential as a reliable, invasive predictor of HH in UC, with implications for improved disease monitoring.