A digital deflection control system in a projection TV is provided which digitally integrates the configuration for converting the digital horizontal deflection signal outputted from the DCS into an analog signal to be applied to the deflection coil as an input, thereby reducing the production cost and realizing small-size product. The digital deflection control system includes an EEPROM for storing vertical and horizontal deflection seed data for R, G, B color signals, a CPU for loading each seed data from the EEPROM and performing the first interpolation for the horizontal deflection data, a digital conversion circuit for performing the second interpolation for the vertical deflection data among the data first-interpolated by the CPU, a digital deflection control for performing the third interpolation for the horizontal deflection data among the data second-interpolated by the digital conversion circuit, a D/A converter for outputting the data third-interpolated by the digital deflection control as an analog signal in the form of step wave, and a filter for removing high frequency component from the signal in step waveform outputted from the D/A converter.