Abstract: This paper presents a reachability model of Virtual Software Research and Development Organizations（VSR&DO） based on network，and proposes a model to estimate the reachability of VSR&DO，which is based on the analysis of the process of VSR&DO model，at the same time to research the reachability of production software.This paper provides four basic structures and a computing model of VSR&DO after researching the characteristic and relations among members，and discusses the whole reachability model of VSR&DO.

摘要： 以建立面向网络的虚拟软件研发组织（VSR&DO）过程建模为目标，在分析VSR&DO运作过程特性的基础上，提出了一种VSR&DO过程模型，并对其软件研发项目的可达性进行了研究。针对VSR&DO自身的特点及成员之间的关系，提出了VSR&DO的四种基本结构，给出了相应的模型和可达性分析，并在此基础上讨论了整个VSR&DO可达性模型。