To study the influence of hidden weld between the overlapped brace and chord on mechanical properties of overlapped CHS-to-SHS N-joints, two partially overlapped specimens with hidden seam weld and two without hidden weld were tested under monotonic loading. The test results showed that when the overlapped brace was in tension, the absence of hidden weld reduced the bearing capacity of joints, and the increased overlapped ratio decreased the joint bearing capacity obviously. Furthermore, weld crack appeared for all specimens without the hidden weld. Based on the experimental results, a finite element model was generated and validated. Using this model, the effects of loading hierarchy reversal of the braces and the hidden seam weld were studied on the response of totally 324 overlapped CHS-to-SHS N-joints with different geometric parameters. It revealed that the absence of hidden weld had less influence on the bearing capacity of the through-brace-in-compression joints than that of through-brace-in-tension joint. In view of the fact that the steel hollow section truss was assembled first and then welded, design suggestions were given.