The invention discloses a particle filtering tracing method and a tracing device thereof. The method comprises the steps as follows: Step S1, samples are collected from the original image frame to obtain an initial particle set; Step S2, foreground and background classifications are carried out to the pixel of the original image frame to obtain a probability graph; Step S3, particles are spread according to a system dynamic model and sampling is carried out, thus obtaining the second particle set; Step S4, the weight of the second particle set is obtained from a system observation model built on the probability graph and the third particle set is obtained by normalizing the weight of the particles; Step S5, importance sampling is carried out to the third particle set, thus obtaining an importance sampling particle set; and Step S6, the system state is calculated by the importance sampling particle set and output. The method and the device improve the calculation efficiency of particle filtering, improve the robustness and are not easy to lose objects.