The interference self-locking hydraulic outrigger has obvious advantages of good locking rigidity and high locking position accuracy.However,the locking performance is significantly affected by the ambient temperature,friction coefficient and locking position,and there are interactions among various parameters.The locking performance of interference self-locking hydraulic outrigger was studied by orthogonal method.Based on the ambient temperature,friction coefficient and locking position and the corresponding five levels in the actual working condition,the orthogonal design was carried out.The variation of the locking force of the hydraulic outrigger was obtained by finite element method,and the influence of the three factors on the sensitivity of locking force was studied.The influence of various factors on the locking force of hydraulic outrigger was analyzed by range method and variance method.It is found that the friction coefficient has the greatest influence on the locking force,followed by the environmental temperature,and the locking position has the least influence.The function relationship between the locking force and the ambient temperature,friction coefficient and locking position was established by regression analysis,and the validity of the equation was verified by numerical simulation,which provided a reference for the design and development of interference self-locking hydraulic outrigger.