The present disclosure relates to a component structure, a power module and a power module assembly structure having the component structure. The component structure comprises: a first bus bar, having one end extending to a first plane to form a first connecting terminal; a second bus bar, comprising a front portion of the second bus bar and a rear portion of the second bus bar, wherein the front portion of the second bus bar is laminated in parallel with the first bus bar, and the rear portion of the second bus bar is extended to a second plane to form a second connecting terminal; and an external circuit comprising a third bus bar, wherein the third bus bar is settled in parallel with the rear portion of the second bus bar, to reduce a parasitic inductance between the first connecting terminal and the second connecting terminal.