The utility model discloses a source-spacing-adjustable acoustic logging sonic system. The source-spacing-adjustable acoustic logging sonic system comprises a receiving nipple assembly, a source spacing nipple assembly, an emitting nipple assembly and a first centralizer, wherein the receiving nipple assembly, the source spacing nipple assembly, the emitting nipple assembly and the first centralizer are connected in sequence in a threaded mode, the receiving nipple assembly comprises a receiving circuit nipple and a receiving probe nipple, the emitting nipple assembly comprises an emitting probe nipple and an emitting circuit nipple, the receiving probe nipple and the emitting probe nipple are respectively encapsulated by two bags, silicone oil is filled inside the bags, and cylindrical steel-made outer shells are respectively arranged on the outer portions of the two bags. The source spacing nipple assembly is formed by disassembly and combination of sound insulators, centralizers and flexible nipples. According to the source-spacing-adjustable acoustic logging sonic system, the emitting probe nipple and the receiving probe nipple are respectively arranged in two different cylindrical steel-made outer shells, the aim of changing sonic system source spacing is achieved through change of the number of the sound insulators, the number of the centralizers and the number of the flexible nipples, and the aim of probing geologic structures with different depths is finally achieved.