There is a failure phenomenon in the estimation of high elevation angle byusing thetraditional parallel linear array. This paper analyses the failure phenomenon and the causeaccording to the structural characters of the array. Thenon this basis,a threelinear array is designed and four crosscorrelation matrixesare calculated on the characteristic of its structure. Thesignal space isobtained via the eigendecomposition of thelarge matrix constructed by the four crosscorrelation matrix. Finally the two dimensional angle iscomputedthrough the Esprit arithmetic. The failure phenomenon could be avoided because of the independent estimation of the elevation angle. The simulation result indicates the effectiveness of the threelinear array.