Surgical resection (SR) following transarterial chemoembolization (TACE)-based downstaging is a promising treatment for unresectable hepatocellular carcinoma (uHCC), and identification of patients at high-risk of postoperative recurrence may assist individualized treatment. To develop and externally validate pre- and postoperative prognostic models integrating multimodal CT and DSA features as well as clinico-therapeutic-pathological features for predicting disease-free survival (DFS) after TACE-based downstaging therapy. From March 2008 to August 2022, 488 consecutive patients with BCLC A/B uHCC receiving TACE-based downstaging therapy and subsequent SR were included from four tertiary-care hospitals. All CT and DSA images were independently evaluated by two blinded radiologists. In the derivation cohort (n=390), the XGBoost algorithm was used for feature selection, and Cox regression analysis for developing nomograms for DFS (time from downstaging to postoperative recurrence or death). In the external testing cohort (n=98), model performances were compared with five major staging systems. The preoperative nomogram included over three tumors (HR, 1.42; P=0.003), intratumoral artery (HR, 1.38; P=0.006), TACE combined with tyrosine kinase inhibitor (HR, 0.46; P<0.001) and objective response to downstaging therapy (HR, 1.60; P<0.001); while the postoperative nomogram included over three tumors (HR, 1.43; P=0.013), intratumoral artery (HR, 1.38; P=0.020), TACE combined with tyrosine kinase inhibitor (HR, 0.48; P<0.001), objective response to downstaging therapy (HR, 1.69; P<0.001) and microvascular invasion (HR, 2.20; P<0.001). The testing dataset C-indexes of the pre- (0.651) and postoperative (0.687) nomograms were higher than all five staging systems (0.472-0.542; all P<0.001). Two prognostically distinct risk strata were identified according to these nomograms (all P<0.001). Based on 488 patients receiving TACE-based downstaging therapy and subsequent SR for BCLC A/B uHCCs, we developed and externally validated two nomograms for predicting DFS, with superior performances than five major staging systems and effective survival stratification.