As one of the promising nano-materials for energy absorption and dissipation, viscoelastic properties of randomly entangled carbon nanotube (CNT) networks subjected to cyclic tension loading are investigated with coarse-grained molecular dynamic simulations (CGMD). The effect of temperature, loading frequency, pre-strain of carbon nanotubes, physical binders and chemical crosslinks on the storage and loss moduli of CNT networks as well as the micro-mechanical mechanisms is mainly focused. Not only the storage modulus but also the loss one is found to be independent of the temperature. However, both of them can be enhanced greatly by the bundle-rich microstructures induced by pre-strain. Furthermore, physical binders and chemical crosslinks can also be used to tune the viscoelastic properties of CNT networks. All the findings should be helpful not only for understanding the mechanical mechanism of CNT networks but also for optimal designs of advanced energy absorption and dissipation materials.