The invention provides a target detection method based on two-dimensional sliding window robust space-time self-adaptive processing, which can increase the accuracy of target detection. The target detection method comprises the steps of : step 1, receiving echo data through an airborne radar; step 2, carrying out space-time sliding window processing on the echo data; step 3, establishing a target apparent steering vector error boundary matrix; step 4, calculating an autocorrelation matrix of projectional component of the echo data after space-time sliding window processing on an orthogonal complementary space of a subspace formed by the target; step 5, calculating a correlation matrix after diagonal loading of the autocorrelation matrix; step 6, solving a weight vector; step 7, judging whether a module value of a column vector obtained through multiplying a conjugate transpose matrix of the boundary matrix by the weight vector is less than 1, if so, increasing loading factors and then executing step 5 and step 6, otherwise, regarding the weight vector as the optimal weight vector; and step 8, constructing a filter by utilizing the optimal weight vector so as to filter the echo data after space-time sliding window processing, and acquiring target echo data.