Abstract: In order to investigate the force transfer mechanism and the performance of typical tower leg joint of transmission steel tubular tower, a multi-scale finite element model is built based on the tangent tower TZ2. The stress distribution of the tower leg joint under design load is analyzed and the plastic extension process is studied under ultimate load. Three simplified tower leg joints are manufactured at full scale and tested under static loadings. Stress distribution, plastic development, failure pattern and ultimate bearing capacity under the secondary moment are investigated. Test results are compared with the results of simplified joint model and multi-scale model. Through experimental study combined with numerical calculations, it is found that the ultimate failure pattern of the joint is the local bulging destruction of the main member above the ring plate, and the secondary stress ratio (bending stress divided by axial stress) accounts for less than 30%, which can be ignored when designing.