The spectrum estimation method which is based on the eigenstructure of array signal correlation matrix is one of the main parameter estimation methods. With the deep-going research in application, the requirement for two dimensions parameters estimations becomes more and more urgent. In this paper, the dimension-separated coupling problem in 2D-MUSIC algorithm is discussed. Though the discussion, the characteristic of coupling array which is decided by the linear correlation between horizontal axis vector and vertical axis vector of array is obtained. And the characteristic shows that larger sensor redundancy exists in the traditional planar array. On the basis of this, An F-shaped array for 2D-DOA estimation is presented, with which, the decoupling 2D-MUSIC algorithm in the dimension-separated manner is implemented. Though analysis and simulation, and in comparison with other algorithms, this algorithm is less in computation load, higher in precision and sensor utilization rate.