Objective: To explore the application value of multi-slice spiral CT (MSCT) in the diagnosis of primary liver cancer and the evaluation of therapeutic effect of transcatheter arterial chemoembolization (TACE). Methods: A total of 79 patients with liver space-occupying lesions admitted to the hospital from May 2022 to June 2025 were selected. All patients underwent MSCT examination. The pathological result was used as the gold standard for diagnosis, and the diagnostic value of MSCT in the diagnosis of primary liver cancer and the efficiency on evaluating the therapeutic effect of TACE were analyzed. Results: Among the 79 patients, pathological diagnosis showed 62 cases of primary liver cancer (liver cancer group). The sensitivity, specificity and accuracy of MSCT in the diagnosis of primary liver cancer were 93.55% (58/62), 94.12% (16/17) and 93.67% (74/79) respectively, revealing a good consistency with pathological diagnosis (kappa=0.824). After TACE treatment, the hepatic blood flow volume, hepatic artery perfusion volume and mean transit time of 62 patients with primary liver cancer were significantly less or shorter than those before treatment (P<0.05), and the time to peal was significantly longer than that before treatment (P<0.05). After TACE treatment, there were 40 cases in effective group and 22 cases in ineffective group. The hepatic blood flow volume, hepatic artery perfusion volume and mean transit time in effective group were significantly less or shorter (P<0.05), and the time to peak was significantly longer compared to ineffective group (P<0.05). ROC curve showed that the AUC of the combination of MSCT parameters for evaluating the therapeutic effect of TACE in patients with primary liver cancer was 0.964 (P<0.05), and combined evaluation had higher efficiency. Conclusion: MSCT can directly reflect the blood supply status of lesions. The results of its diagnosis of primary liver cancer show a good consistency with pathological diagnosis, and it has significant value on evaluating the therapeutic effect of TACE.