Objective To analyze the clinical application value of high-resolution CT (HRCT) combined with CT thin-layer reconstruction technology in acute appendicitis. Methods A total of 86 suspected acute appendicitis patients admitted to the Henan Electric Power Hospital from January 2023 to January 2025 were selected. All patients underwent HRCT scanning and CT thin-layer reconstruction technology examination before surgery, all of whom met the surgical indications and received surgical treatment. The postoperative pathological results as the“ gold standard” to analyze the detection rate, diagnostic efficacy, and differential diagnostic value of HRCT combined with CT thin-layer reconstruction technology for acute appendicitis of different pathological types. Results Out of 86 suspected patients with acute appendicitis, 72 were diagnosed with acute appendicitis through surgery, accounting for 83.72%. Surgical results were used as“ gold standard”, the detection rates of acute appendicitis by HRCT and CT thin-layer reconstruction alone and in combination were 84.72% (61/72), 91.67% (66/72), and 100% (72/72), respectively. The combined detection rate was higher than that of the two examinations alone (χ2＝11.910, 4.348, all P＜0.05). The sensitivity, accuracy, and negative predictive value of joint diagnosis were 100%, 97.69%, and 100%, respectively. The sensitivity was higher than that of HRCT and CT thin-layer reconstruction alone, and the accuracy and negative predictive value were higher than HRCT examination (all P＜0.05). The accuracy of joint examination in differentiating the pathological types of acute appendicitis was 95.83% (69/72), which was highly consistent with“ gold standard” (Kappa ＝0.937, P＜0.001). Conclusion HRCT combined with CT thin-layer reconstruction technology can improve the accuracy of the diagnosis of acute appendicitis, which is highly consistent with“ gold standard” and provides reliable imaging evidence for individualized treatment decisions in clinical practice.