Disclosed is an active DTV amplifier for amplifying signals and detecting and displaying the intensity of signals of an antenna. The amplifier is connected between the antenna and a coaxial cable and includes a primary signal amplification circuit connected to the antenna for performing a primary amplification of a captured antenna signal, a secondary signal amplification circuit connected to the coaxial cable for performing a secondary amplification of the antenna signal and outputting the amplified signal to a feeder coaxial cable, a signal shunt circuit for splitting and the antenna signal processed by the primary amplification into two and assigning the split signals to the single detection circuit and the secondary signal amplification circuit, and a single detection circuit connected to a microcontroller for feeding the collected antenna signal back to the microcontroller which is connected to a display screen to instantly display the intensity of the signal.