Abstract: The interference characteristics of towed platform noise resulted from propeller and towed body noise for active/passive towed array is analyzed. It is shown that, in shallow water environment, the direct wave and bottom/sea surface reflected wave will seriously affect the performance of sonar system. The formula for calculating the direction of arrival (DOA) of interference in various parameters, such as array depth, length of tow cable, is derived. The effect of interference noise for the performance of sonar system is described. The results of system simulation provide the method for reducing the effect of these kind of interferences.