The invention discloses a mechanical and electrical connecting structure between drill collars of while-drilling instruments. By the mechanical and electrical connecting structure, shortcomings of high machining and operating difficulty and low operating efficiency of mechanical and electrical connection among drill collars of while-drilling instruments at present are overcome. The mechanical and electrical connecting structure is characterized in that a hollow first electronic framework is hermetically mounted in an inner hole of a first drill collar, and a hollow second electronic framework is hermetically mounted in an inner hole of a second drill collar; a first end of an inner barrel is positioned in an inner hole of the first electronic framework, and a second end of the inner barrel is positioned in an inner hole of the second electronic framework; the two ends of the inner barrel are respectively hermetically connected with the first electronic framework and the second electronic framework; the first electronic framework is connected with the second electronic framework in a threaded manner; the first electronic framework is electrically connected with the second electronic framework by a jumper wire. The mechanical and electrical connecting structure in an embodiment of the invention has the advantages that the drill collars of the while-drilling instruments are reliably mechanically and electrically connected with each other, and the mechanical and electrical connecting structure can be installed and maintained conveniently and quickly, and is low in difficulty and high in operating efficiency.