Abstract: In order to enhance the shock wave generated by the underwater electrical wire explosion(UEWE) at a fixed energy, two kinds of new wire-array were developed. The first one was made of "split wires" in parallel and the second one was made of wires in parallel and series. In the experiment of UEWE with the wire-array of "split wires" at a fixed energy of 200 J, it is found that the shock wave is greatly enhanced as the number of the "split wires" increases, from 25 MPa with one wire of 0.2mm in diameter to 91 MPa with 16 wires of 0.05 mm in diameter. With the help of a shunt circuit, the shock wave from one single wire in the wire-array was measured and found to be proportional to the diameter of the wire. The shock wave at the axis of the wire-array is simply the summation of the shock waves from all wires. Based on these experimental results, a formula for calculating the shock wave from the wire-array of "split wires" was deduced. In the experiment of UEWE with the wire-array of wires in parallel and series, it is found that the wire-array of wires in series helps make a breakthrough in the upper limit for the exploding mass at a fixed energy. However, the wire-array of wires in series is not always better than that in parallel. When the deposition energy is high enough for a full vaporization of the wire-array, a high deposition power is crucial for a strong shock wave. Therefore, the wire-array of wires in parallel and series may be the best choice. A method for optimizing the design of a wire-array of wires in parallel and series is given.