The utility model discloses a portable low discharge sample thief noise reduction box, include and fall the cotton inner tube I of making an uproar, cool off the inner tube and fall II concentric cylinders that reduce in proper order for the same bottom surface of generating line radius of cotton inner tube of making an uproar to the subtracting the outer box of vibrating plate, falling the cotton inner tube I of making an uproar, cooling inner tube, falling the cotton inner tube II of making an uproar of interior setting by outer, form the cooling space between II cooling off the inner tube and fall the cotton inner tube of making an uproar. The utility model discloses portable noise reduction box compares prior art, and the structure is simpler, and the volume is less, convenient to use, portable, effectively noise reduction and environmental protection. And place cutting head and pipeline outside noise reduction box, can reduce unnecessary experimental error.