A recognition algorithm of heart rhythm capable of electric shock cardioversion based on standard deviation fo the standardized slope absolute value, is suitable for disease diagnosis and treatment instrument or apparatus, including the steps: S1, preprocessing the electrocardiosignal; S2, recognizing whether the electrocardiosignal is the heart rhythm of cardiac arrest, if so, judging the heart rhythm as the heart rhythm incapable of electric shock cardioversion, otherwise, continuing the follow-up steps S3 and S4; S3, calculating the standard deviation of the standardized slope absolute value; S4, determining whether it pertains to the heart rhythm incapable of electric shock cardioversion or the heart rhythm capable of electric shock cardioversion based on the standard deviation of the standardized slope absolute value. The invention improves the sensitivity and specificity of recognizing the heart rhythm capable of electric shock cardioversion, simplifies the computational complexity of the algorithm, can be applied to the existing ECG guardianship equipment and automatic external defibrillator, and the like instruments requiring body surface electrocardiogram for recognizing the heart rhythm capable of electric shock cardioversion.