The invention provides an installing and fixing component for an exhaust system and the exhaust system. The installing and fixing component comprises a first buffer block and a second buffer block, wherein a fixing screw nut and a first through hole are arranged on the first buffer block; the first through hole communicates with a threaded hole of the fixing screw nut; the first through hole penetrates through the first buffer block; the second buffer block comprises a buffer base and a projected part fixedly connected onto the buffer base; a second through hole penetrates through the buffer base and the projected part; the inner wall of the second through hole is fixedly connected with a tubular support element; the projected part passes through a first installing hole formed in a first support frame; then, the first buffer block is arranged on the projected part in a sleeving way; the screw bolt sequentially passes through a second installing hole, the tubular support element and the first through hole formed in the second support frame to be matched with the fixing screw nut through screw threads. Therefore by using the technical scheme of the installing and fixing component and the exhaust system provided by the invention, the vibration of the exhaust system is isolated from an automobile body; the vibration transmitted onto the automobile body is reduced; the taking feeling of passengers is improved.