A computation apparatus, a cardiac arrhythmia assessment method thereof and a non-transitory computer-readable recording medium are provided. In the method, electrocardiography (ECG) signal is obtained. Whether the ECG signal is conformed to a first abnormal rhythm symptom is determined. Then, whether the ECG signal is conformed to a second abnormal rhythm symptom different from the first abnormal rhythm symptom is determined based on the determined result of the first abnormal rhythm symptom. Accordingly, multiple abnormal rhythm assessments are integrated, the subsequent assessment is speeded-up and optimized according to the determined result of a previous assessment, so as to enable to implement on a handheld apparatus.