Herein, we successfully developed a novel three-dimensional framework attached carbon nanotubes deposited with high density of gold nanoparticles (Au NPs-CNTs/3DF) through a facile method. The achieved hybrid with an opened hierarchical network was effectively used as a free-standing sensor for hydrazine detection. The catalytic activity of the proposed sensor was impressively higher than those of other surveyed materials, such as CNTs/3DF and Au NPs/3DF. In this regard, the much higher intensity of oxidation current density and negative peak potential were presented for Au NPs-CNTs/3DF towards hydrazine oxidation. Through amperometric measurements, the Au NPs-CNTs/3DF electrode displayed excellent performance for hydrazine determination with wide linear detection range of 0.5 to 483μM, high sensitivity of 1.65μA·μM−1·cm−2, a low detection limit of 1.1μM, along with negligible interference effect. The obtained results suggest that the Au NPs-CNTs/3DF hybrid holds the great prospect for highly sensitive and selective determination of hydrazine in practical applications.