The temporal instability of a particle-laden jet was investigated numerically which took into consideration the parametric effects of jet parameter, B, jet Reynolds number, Re(j), particle mass loading, Z and Stokes number, St. The linear stability theory was used to derive the instability equations of a viscous particle-laden jet flow. The single-phase instability of a top-hat jet was then calculated and compared with the available analytical theories. The numerical results agree well with the analytical results for both the axisymmetric (n = 0) and first azimuthal (n = 1) modes. The results show that the first azimuthal mode disturbance is usually more unstable than that of the axisymmetric mode. But the axisymmetric mode disturbance can be more unstable when Z is high enough (i.e., Z >= 0.1). The higher B and Rej are, the more unstable the particle-laden jet will be. The existence of particles enhances the flow stability. With the increasing of Z, the jet flow will grow more stable. The inviscid single-phase jet is the most unstable. The wave amplification, c(i) first decreases with the increasing of St and then increases afterwards. There exist certain values of St, at which the jet is the most stable. (c) 2007 Elsevier Ltd. All rights reserved.