The invention discloses a partial sparse L array and a two-dimensional DOA estimation method thereof. Two subarrays for the L array, the array element interval of the first subarray is half of a wavelength, and the array element interval of the second subarray is n times of the wavelength; and an auxiliary array element distanced half of the wavelength away from a reference array element is arranged on the second subarray. During DOA estimation processing, the subarrays are respectively placed on an x axis and a z axis, and by use of a feature that a cross-correlation matrix is not affected by noise, cross correlation of receiving data is solved, and a signal subspace is extracted; by use of translation invariability of a ULA and the signal subspace, a rotation matrix of a z-axis array flow type matrix is solved, possible pitch angle estimation values are obtained by performing feature value decomposition on the rotation matrix, and then defuzzificaiton processing is performed on estimation results based on the auxiliary array element; and then based on this, a source waveform and an x-axis array flow type matrix are estimated, and corresponding azimuths are solved. The partial sparse L array and the two-dimensional DOA estimation method thereof are applied to radar, sonar and the like, and have the advantages of low realization cost, low computation quantity and high direction finding precision.