Abstract: The present disclosure designs a rotation matrix-based factor graph cooperative localization algorithm. Firstly, the reasons of sudden increase in an error in an operation process of a conventional factor graph cooperative localization algorithm are analyzed; secondly, a rotation matrix is designed, and the size of a rotation angle is determined; then, a rotation matrix-based cooperative localization algorithm factor graph model is constructed, and a specific algorithm flow is designed; and finally, filtering fusion estimation is performed on position status information of a slave boat.