Kneading time effect on electrical properties of SWCNT reinforced polyamide 6 (SWCNT/PA6) nanocomposites was investigated in detail by impedance spectroscopy. In-situ polymerization method was applied for sample preparation. As received (AR) and wet jet milling (WJM) method treated SWCNTs were both used as two kinds of fillers. IS results indicated that the electrical conductivity in both ARSWCNT/PA6 and WJM-SWCNT/PA6 nanocomposites can get an improvement under suitable kneading treatment, but with longer kneading time, the dielectric property would be enhanced. Moreover, IS results showed that WJM-SWCNT/PA6 nanocomposites had a higher electrical conductivity (6.5 x 10(-2) S/m) than AR-SWCNT/PA6 nanocomposites (1.9 x 10(-2) S/m), which has been attributed to be from different network distribution state of AR-SWCNTs and WJM-SWCNTs. This study indicates that electrical and dielectric properties of CNT based polymer nanocomposites can be effectively controlled by adjusting kneading time, and lower percolation threshold could be potentially achieved by suitable kneading time and morphology treatment of CNTs. (C) 2015 Elsevier Ltd. All rights reserved.