An entropy balance equation including the transfers of heat and mass, work of external force of the ocean is presented and discussed. Entropy flux through the sea surface are calculated, and the results show that entropy flux due to heat transfer is about -555.6 mWm-2K-1, entropy flux connected with the work of wind stress is relatively smaller at about -0.09 mWm-2K-1, entropy flux due to mass transfer is -0.02 mWm-2K-1, the sum of all the entropy flux is -555.7 mWm-2K-1, the mean rate of generation of entropy inside the ocean must be 555.7 mWm-2K-1 when the ocean is in a climatic steady condition.