Abstract: This paper established a statespace simulation model of the monthly fluctuation patterns between the Nosopsyllus laeviceps kuzenkovi and Meri ones unguiculatus. It consisted of the following formulas: x_t+1=-0.33 6x_t+0.057y_t+0.107z_t, y_t+1=0.586x_t-0.369y_t-0.274z_t, z =0.189x_t+0.247y_t-0.309z_{t, where xt is the population de nsity of M. unguiculatus, yt and zt are respectively related to th e burrow nest and the body flea index of N. l. kuzenkovi at t month. Th e simulation results exhibited satisfactory agreement with field data. The population density of M. unguiculatus was the main fac tor affecting the burrow nest flea index of N. l. kuzenkovi.}

Key words: Nosopsyllus laeviceps kuzenkovi, Meriones unguiculatus, rat burrow nest flea index, rat body flea index, population density, statespace model, Nosopsyllus laeviceps kuzenkovi, Meriones unguiculatus;rat burrow nest flea index, rat body flea index, population density, statespace model