The spontaneous emission properties of emitters in dielectric-loaded surface plasmon polariton (DLSPP)waveguide are investigated.The expressions for both the spontaneous emission rate and the probability of spontaneous emission coupled into SPP mode of an emitter in SPP waveguide are derived with a dipole approximation.Then,the spontaneous emission rate and the probability of spontaneous emission coupled into SPP mode of the rhodamine 6G (R6G) particle in the single-mode DLSPP waveguide are calculated numerically.The results show that the spontaneous emission rate of the particle increases when the particle is near the metal interface while decreases and inclines to the value in the vacuum when the particle is away from the metal interface.Meanwhile,the probability of spontaneous emission coupled into SPP mode is also position-related,and may reach about 70% when the particle is located in the center part of the cross-sectional area of the waveguide.With those simulation results,it may be predicted that both the maximum achievable average population inversion and the efficiency of spontaneous emission coupled into SPP mode of the particles over the cross-sectional area of the waveguide may be improved by optimizing the particle-doped distribution.