The present study employs a combination of numerical and analytical techniques to examine the detonation flows of explosives containing compressible inert particles. A two-phase numerical model incorporating the compressibility of the particles is developed, and the two-phase detonation process is simulated under the Lagrangian framework, where the explosive and the particles are treated as a fluid and discrete spheres, respectively. For small velocity difference between phases, a perturbation method is utilized for the analysis of the dynamics of the detonation front, the detonation product, and the particles. The effects of the particles' compressibility and material density are examined in detail. The results show that the material density of the particles exerts a linear influence on the detonation flow of the explosive, while the effects of the particle compressibility are much more complex. An increase in the particle's material density or compressibility can reduce the velocities of both the detonation front and the flowing-stagnant boundary. The jump of the particle volume fraction across the detonation front relies on the particle compressibility. For more compressible particles, the particle volume fraction exhibits a non-monotonic behavior in the flowing region. A concise scaling law is also obtained for the velocity difference between phases. The present research provides a quantitative prediction to the effects of compressible particles on the detonation flows of explosives.