Objective: To investigate the value of cardiac color Doppler ultrasound (CDUS) in determining the clinical characteristics and assessing the prognosis of patients with chronic heart failure (CHF). Methods: 200 patients with CHF admitted to our hospital from January 2021 to June 2023 were selected as the study subjects, and these 200 patients were followed up for 6 months, with 159 cases in the surviving group and 41 cases in the deceased group, and examined with a diagnostic CDUS instrument (model GEVividE95ACUSONSC2000). The detection rate of chronic heart failure and cardiac function indexes of the two groups were observed. Results: The deceased group showed a chronic heart failure detection rate of 92.68%, which was significantly higher than the surviving group (76.73%; P < 0.05). Moreover, the cardiac function indexes of both groups were significantly different (P < 0.05). Conclusion: By performing cardiac ultrasonography on patients with CHF, their cardiac function can be clearly understood and the changes can be timely detected during treatment, hence physicians can formulate a more reasonable treatment plan for patients and improve their quality of life.