Aimed at the problem that the traditional sparse array is hard to realize direction finding error caused by the synchronization optimization of aperture and mutual coupling, an interelement spacing restriction array with high degree of freedom and low mutual coupling is designed. The array is composed of four uniform linear arrays connected from beginning to end at a certain interval, and the restriction at which the array element spacing of each uniform linear array and the space between each uniform linear array are as large as possible is done, thus forming three sparse uniform linear arrays and one dense linear array, and effectively reducing the mutual coupling effect among array elements. Based on this array, the closed solutions of physical array element position and difference joint array and the closed solutions of degree of freedom are derived. Compared with the traditional and improved sparse arrays with the same number of array elements, the designed interelement spacing restriction array has larger aperture, lower mutual coupling and more continuous virtual array elements. The advantages of interelement spacing restriction array are verified by experimental simulation.