The present competitive situation between short-term bond and corporate bond makes it possible that small and middle companies issuing corporate bond，but some real problems such as market timing， credit rating， issurance companies， pricing mechanism and so on still are difficulty. According to the history of junk bond in American， and extrusion effect showing in Japan and Korea corporate bond market，this paper thinks that it is worth optimizing the issue order of different corporate bonds， innovating the model of collection bond， establishing junk bond funds， perfecting bond pricing mechanism and so on.