The existing literature does not include quantitative discussion of the super resolution performance of RELAX algorithm or the content of the boundary conditions analysis of RELAX application, resulting in the practical application of RELAX algorithm is very difficult. Based on the detailed analysis of the super resolution principle of RELAX algorithm, a number of boundary conditions about the practical application of RELAX are given through simulation, and four practical conclusions are drawn that can guide the RELAX algorithm in the application of actual scattering center estimation: a) RELAX super resolution processing is not sensitive to the number of estimated scattering centers; b) when the number of FFT points is about twice that required to achieve the true resolution, the reconstruction accuracy of RELAX super resolution processing can meet the requirement; c) when ensure a certain degree of reconstruction accuracy, the maximum resolution of RELAX super resolution processing can raise up to twice the actual resolution; d) under the simulation conditions in this paper, when RSN=10 dB, RELAX super resolution processing is basically available within a certain error tolerance range.