The invention provides a thermal storage tank capacity optimization configuration method used for increasing a wind power absorption ability and a system thereof. The method comprises the following steps of establishing a thermal storage tank capacity optimization configuration model which includes a thermal storage tank capacity optimization configuration target function and a corresponding constraint condition; and using a branch and bound method to solve the thermal storage tank capacity optimization configuration model and completing thermal storage tank capacity optimization configuration. By using the thermal storage tank capacity optimization configuration method used for increasing the wind power absorption ability and the system thereof, randomness and fluctuation performance of wind power output, a thermal load demand of a user and thermal storage and release characteristics of a thermal storage tank are integratedly considered so as to realize flexible output adjusting of a heat supply unit and increase a wind power utilization rate.