Provided are a data receiving apparatus that can determine data by adjusting a reference level for determining a logic value of inputted data based on Inter-Symbol Interference in a data signal inputted through a transmission line, and receive the data without errors by compensating for timing margin decrease caused by the inter-symbol interference, and a method thereof. The apparatus includes: a reference generator for monitoring the level of an inputted data signal or generating reference levels according to an external control command; a comparator for comparing the inputted data with the reference levels and determining logic values of the inputted data; a selector for selecting the logic values of the inputted data as a valid logic value; and a selection controller for monitoring the valid logic value of the selector, transmitting a selection control signal to the selector, and controlling a process for selecting the valid logic value.