We report on the fabrication and characterization of a novel terahertz detector based on the GaN/AIGaN high electron mobility transistor (HEMT) which includes the bowtie antenna and terahertz filter.With the help of the antenna,the terahertz electromagnetic wave can be resonantly coupled to the 2D electron gas with proper transverse and longitudinal electric fields.This device can produce a dc photocurrent at the room temperature by the self-mixing mechanism.We also introduced a low pass filter to isolate the high frequency electromagnetic field from the electric bonding pad,which may reduce the detectors sensitivity by weakening the resonance of the antenna.With the aid of the antenna and filter,our HEMT device achieves high sensitive THz detection at the room temperature.The equivalent noise power (NEP) and responsivity of our detector are estimated to be 500uW/Hz0.5 pHz and 26mA/W at 300 K,respectively.