A method for controlling an upload size of data by a device is provided. The method includes determining whether to change a size of data to be uploaded based on a policy of an upload target server, upon determining to change the size of the data to be uploaded, determining an initial transfer size of the data, and uploading a part of the data corresponding to the determined initial transfer size, updating an upload result of the partial data in an upload history, and determining a next transfer size for the data depending on a reception result of the part of the data from the upload target server for a period obtained from the policy.