  Mapping a complex network of $N$coupled identical oscillators to a quantum
system, the nearest neighbor level spacing (NNLS) distribution is used to
identify collective chaos in the corresponding classical dynamics on the
complex network. The classical dynamics on an Erdos-Renyi network with the
wiring probability $p_{ER} \le \frac{1}{N}$ is in the state of collective
order, while that on an Erdos-Renyi network with $p_{ER} > \frac{1}{N}$ in the
state of collective chaos. The dynamics on a WS Small-world complex network
evolves from collective order to collective chaos rapidly in the region of the
rewiring probability $p_r \in [0.0,0.1]$, and then keeps chaotic up to $p_r =
1.0$. The dynamics on a Growing Random Network (GRN) is in a special state
deviates from order significantly in a way opposite to that on WS small-world
networks. Each network can be measured by a couple values of two parameters
$(\beta ,\eta)$.
