This paper studies the synchronizability and the synchronization processes of three kinds of clustered networks with different inter-cluster couplings, where each clustered network is composed of two BA scale-free subnets. The clustered network is called a TWD network if the inter-cluster coupling is a two-way coupling, but it is called a BDS network if the small subnet is driven by the big one, and is called an SDB network if the big subnet is driven by the small one. The result shows that when the ratio of node number of small subnet to that of big one is larger than a critical value, the whole synchronizability of the TWD networks is better than that of the BDS networks; however, when this ratio is smaller than the critical value, the whole synchronizability of the TWD networks is weaker than that of the BDS ones, the whole synchronizability of the SDB networks is always the worst. For a one-way-driven clustered network, the synchronizability is just related to the node number of the driven subnet and the number of the inter-links, but has nothing to do with the node number of the driving subnet. The increase in the inter-links can reduce the synchronous speed of the subnet at the beginning but may enhance the synchronizability of the whole network eventually. The Kuramoto phase oscillators are taken as the network nodes to further study the synchronization process of the three-clustered networks for different cases, and the correctness of the above conclusions are evidenced.