Through the noise factor theory of amplified spontaneous emission of Surface Plasmon Polaritons (SPPs), the variations of noise factor of Long Range Surface Plasmon Polaritons(LRSPPs) were studied.And a waveguide structure with strips embedded in the metal film of LRSPPs structure is designed.Numerical simulation is used to get the noise factor variations of SPPs and LRSPPs.In the numerical simulation, incident wavelength ranges from 0.5 μm to 1.75 μm, and check the characteristics of noise factors for every 0.25 μm, the results show that the noise factors approach to a constant value with the increase of wavelength.The simulation results show that the noise factor of the amplified spontaneous emission of the SPPs and the LRSPPs are enhanced apparently with the increase of grain mediums;noise factors of periodic stripe LRSPPs are increased as the thicknesses of metal film and the height and the number metal strip are increased, where the impact of the thickness of metal film is relatively evident.