Direction-finding cross positioning is simple and requires less measurement information, which is widely used in the field of passive positioning.It is difficult for the traditional direction-finding cross positioning algorithm to solve the positioning problem when the number of targets is unknown.To solve the problem, a direction-finding cross positioning algorithm based on grid density peak is proposed, which introduces meshing and density peak clustering into direction-finding cross positioning, and uses Hough transform to formulate a rule for picking cluster centers.According to the results of simulation experiments and measured data experiments, it is proved that the proposed algorithm can automatically identify the number and position of targets in the presence of noise.It has strong robustness, which can be applied to practical problems.