The expanding ANFO explosive was produced by expanding ammonium nitrate (AN) and fuel oil (FO) with mass ratio of 94.5：5.5. To obtain low detonation velocity expanding explosive，commercial attenuant was blended into the expanding ANFO explosive. Then，the detonation velocity and density of compound explosive was measured on the condition of nature pile-up state and different loading thickness. Results show that detonation velocity of compound explosive declines from 3100 m·s^-1 to 2100 m·s^-1 when mass ratio of attenuant rises from 20% to 60% (explosive loading thickness is 30 mm )，and the density of compound explosive rises from 0.615 g·cm^-3 to 0.76 g·cm^-3 when mass ratio of attenuant rises from 20% to 50%. The detonation velocity of compound explosive with 50% attenuant content is 2300-2360 m·s^-1，when the explosive loading thickness is 25-50 mm. SS304 cladding to 16MnR experiment was performed by using compound explosive with 35% attenuat content，and the results show that the compound explosive can be used in metal explosive welding.