The noise performance of resonant tunneling diode photodetector (RTDPD ) with an In0.52Al0.48As multiplication region is analyzed in this p aper.The structure of the detector is designed with a multiplication structure for electron multiplication and an AlAs/In0.53G a0.47As/AlAs double-barrier structure for electron tunneling.Current-voltage simulation results show that the photoc urrent and dark current of the detector are magnified after adding a multiplication region,while the peak current is magnified by 1.7times.Noise distribution of the RTDPD without a multiplication region is s imulated and the results show that the 1/f noise is about 10orders of magnitude higher than shot noise and thermal noise.The electric field intensity in the multiplication region and excess noise factor ar e simulated and the power spectral density of the excess noise is calculated.The results show that the power spectral density of the excess noise rises when the bias voltage increases from 2.5V,and it reaches 4.17×10－24 A²/Hz at 6V. The overall noise of the RTDPD with a multiplication region is analyzed and t he calculated noise equivalent powers of the RTDPDs with and without the multiplication region show that when the detector works at 5－6V,the performance of the detector is enhanced via adding t he multiplication region.