Provided is an apparatus for controlling a data flow for multiple paths in a receiving node of a communication system. The apparatus includes a receiver configured to receive data for a specific sub-flow among a plurality of sub-flows; a controller configured to calculate an optimal transmission rate of the received data, determine a window reference value for generating the optimal transmission rate, and generate an artificial response message if a window size for the specific sub-flow is greater than or equal to the window reference value; and a transmitter configured to transmit the artificial response message to a transmitting node.