To carry out major energy parameters research for the transient electromagnetic excitation coil,according to the magnetic induction vector superposition principle, the design of several simple structure having focusing properties of the excitation coil structure, focusing effect by comparison, mutual size and the difficulty of making merit considering the electRectangle surface arrays, the response surface method focusing coil having a magnetic characteristic parameter optimization. Using electromagnetic simulation software simulation, comparing with the traditional singlecoil, the excitation energy of the magnetic field coil so that the main focus in a radius of less than 0.3 m, and the magnetic flux density within the target area increased 33 percent, to lay the foundation for further practical application, change a rectangular array overlap area is magnetically different depths of focus, good focus to improve the transient electromagnetic method of partial defect detection rate, to achieve accurate detection of parallel and overlapping metal pipe buried the remaining wall thickness.