The realization of controllable couplings between any two qubits and among any multiple qubits is the critical problem in building a programmable quantum processor (PQP).We present a design to implement these types of couplings in a double-dot molecule system,where all the qubits are connected directly with capacitors and the couplings between them are controlled via the voltage on the double-dot molecules.A general interaction Hamiltonian of n qubits is presented,from which we can derive the Hamiltonians for performing operations needed in building a PQP,such as gate operations between arbitrary two qubits and parallel coupling operations for multigroup qubits.The scheme is realizable with current technology.