The invention discloses a method for estimating a two-dimensional direction-of-arrival of a coherent signal source by means of an L-shaped array based on time smoothing. The method is implemented by the steps of: 1, transmitting a multi-period linear frequency modulation signal to a scene in the front by means of an L-shaped array radar, and receiving an echo signal reflected by the scene; 2, performing two-dimensional discrete sampling on the echo signal to obtain a matrix form of the echo signal, and carrying out fourth-order cumulant and time smoothing processing to obtain a covariance matrix; 3, constructing a noise subspace according to the covariance matrix, and constructing a signal subspace according to a matrix placement form; 4, and estimating a direction-of-arrival of a signal source according to orthogonality between the signal subspace and the noise subspace. The method can realize precise estimation of the two-dimensional direction-of-arrival of the coherent signal source, improves the direction-of-arrival estimation performance under a low signal-to-noise ratio, and can be used for measuring space angles of a stationary or moving target.