Abstract: It is generally difficult to localize a weak source for a passive system in the presence of strong interferences. Passive source ranging using a guide source based on the intensity striation is widely concerned due to its little requirement of environmental information. Beam intensity striation has higher processing gain based on a horizontal array, but it still could be confused by the sidelobes of the stronger interferences. In this case, an eigenanalysis-based adaptive interference suppression (EAAIS) method is used to improve the signal-to-noise ratio (SNR) and signal-to-interference ratio (SIR) of the target signal. Then the preprocessed target signal is used to obtain the more accurate and clearer beam intensity striations for passive target source ranging based on a guide source. The experimental results demonstrate the effectiveness and feasibility of the proposed range estimation method.