Abstract: A speaker box structure is configured for mounting to a motorcycle between a front wheel and an engine thereof, and includes a tubular bottom section internally having at least one reflex tube oriented to a ground surface; two tubular bent sections respectively connected to two ends of the tubular bottom section; two tubular connection sections respectively connected to ends of the tubular bent sections opposite to the tubular bottom section; and at least two speaker units respectively connected to the tops of the two tubular connection sections. And, the reflex tube is sequentially communicable with the tubular bent sections and tubular connection sections. With these arrangements, music of improved tone quality can be output via the speaker box structure.