Abstract: Proposed in this paper is an analytical method for the out-of-plane stability analysis of crane jib with double rods． In this method，the effect of lateral flexibility of the fixed joint on the jib stability is considered，and a dimensionless lateral stiffness coefficient is introduced to measure the lateral constraint． Then，by establishing the deformation differential equation in the critical state，the characteristic equations of out-of-plane instability and the corresponding critical force are deduced． It is found that the analytical results are completely consistent with the ANSYS simulation results． Moreover，the expressions of the characteristic equations，respectively in two limited lateral stiffness conditions of the fixed joint and in the degradation case of the jib to single rod，are discussed，and the influence of lateral stiffness of the fixed joint on the stability of the jib is analyzed． The results show that a suitable increment of the lateral stiffness may significantly improve the stability of the jib until the lateral stiffness reaches a certain value．

Key words: double-rod crane jib, out-of-plane stability, differential equation method, fixed joint, lateral flexibility