Network connectivity is an important factor of the performance of wireless Ad hoc networks (WANETs) because it represents the lifetime that a node is connected to an arbitrary one. However, due to the dynamic networks, the connectivity is unstable. Under the WANETs, the influences of the connectivity are investigated. Although various models have been proposed to study the issues, the comparisons under different channels fading are lacking. In order to compare the impacts between different channels, we calculate the isolation probability and the whole network probability whether can be connected under Nakagamim fading and Rayleigh fading two communication channel models in this paper. Moreover, the numerical results show that the presence of two fading channels can greatly affect the connectivity of the wireless Ad hoc networks.