The problem of shock wave turbulent boundary--layer interoction in gas-particle flows through circular ducts is investigated experimentally. The effects of the amount of solids in the air flow, the intake design parameters such as; the upstream driving pressure, intake Mach numbar,duct length and the back pressure on the interaction characteristics have been investigated. The results indicate clearly that the interaction characteristics are mainly affected by the present of solid particles in the air flow and the duct length. A lower pressure recovery is expected as both of the intake Mach number and the amount of solid particles,suspendA in the air, are increased. As the solids loading ratio increases the pressure recovery decreases, while as the duct length increases the shoe interaction becomes stronger.