The invention provides an automatic payment reminding method and system, and relates to the technical field of power information management. The method is applied to a server, an intelligent ammeter and a user terminal which communicate with one another, and a mailing address of the user terminal is stored in the intelligent ammeter. The method comprises that the server obtains power utilization information of a user; the server calculates the predicted power utilization speed of the user according to the power utilization information; the server searches for an electric charge balance threshold that matches the predicted power utilization speed, and sends an electric charge payment reminding signal to the intelligent ammeter when the present electric charge balance of the user is lower than the electric charge balance threshold; in response to the electric charge payment reminding signal, the intelligent ammeter raises the alarm for a second preset time length every a preset time length; and in response to the electric charge payment reminding signal, the intelligent ammeter obtains the mailing address of the user terminal, and sends an electric charge payment reminding information to the user terminal. Thus, the user is reminded of payment of the electric charge automatically, timely and reliably.