Provided is an X-type composite rocket inter-stage section or inter-box section connecting structure. The connecting structure comprises a plurality of X-type inter-stage section/inter-box section connecting pieces (1), a front storage box rear short shell (2) and a rear storage box front shot shell (3), wherein the front storage box rear short shell (2) and a front rocket body/storage box structure (5) are integrally welded to be formed, and the rear storage box/rocket body front short shell (3) and a rear rocket body/storage box structure (4) are integrally welded to be formed. The front ends and the rear ends of the eight X-type inter-stage section/inter-box section connecting pieces (1) are separately and mechanically connected with the front storage box rear short shell (2) and the rear storage box front short shell (3) through anti-shear bolts, the connecting problem of existing rocket inter-stage sections/inter-box sections and inter-box sections of deep space exploration propelling aircrafts is solved, the low heat conductivity of front and rear storage boxes of low-temperature propelling aircrafts is achieved, structure efficiency is improved further and good assembly manufacturability is achieved.