As the existing SpaceWire standard is preliminary due to its lack in dynamic responses to some complex situations in its route section,an improved routing algorithm is proposed to deal with such situations as plug- and-play and a lot of unexpected data that may occur when the static routing table is adopted in SpaceWire.This algo-rithm judges whether to adopt the second- choice route by sending inquiry packets and by learning the sending queue length of the second- choice route,and rationally utilizes other idle routings to improve the link utilization.Moreo-ver,Opnet is used to make the simulation model for experiments.The results indicate that the second- choice route can not only improve the utilization of the link but also shorten the average end- to- end delay,and that the package communication system can weaken the effect of bad situations on the improved routing algorithm.The effectiveness of the improved routing algorithm is thus verified.