Abstract: In the deep space exploration and communication,due to its long distance and complicated environment,it is difficult to communicate and ensure the communication quality.So,an effective method is proposed to construct deep space information networks(DSINs)to resolve these problems.And the deep space backbone network is an important part of the DSINs,the nodes of deep space backbone network responsible for lots of data switching service request,so,analysis related to the traffic distribution of backbone nodes is precondition to guarantee the quality of service(QoS)and communication ability of the entire DSINs.Based on the hypothesis of non-constant service request arrival rate,we get the probability of service request time interval less than a setting time,and also the probability of service requests less than a threshold in a certain period.The results provide a basis for reasonable distribution of traffic and data routing in the deep space communication,and provide guidance in order to avoid traffic congestion.The results can be an intuitive reference in DSINs routing and QoS supply.