Large-scale software development is still considered as an increasing-complexity and effort-consuming expensive activity, albeit the widespread application of software system in the modern society. Given the survey studies of environmental factors defined in software development [3, 4], how can we incorporate the important environmental factors into software reliability modeling to improve the prediction power is an interesting yet challenging research topic. Hence, this paper develops the framework of a generalized software reliability modeling considering multiple environmental factors and the randomness caused by environmental factors. Moreover, the specific software reliability modeling with two specified environmental factors, Percentage of Reused Modules (PoRM) and Frequency of Program Specification Change (FoPSC), is discussed. A numerical example is discussed to compare the predictive power of the proposed model with a recent software reliability model with a single environmental factor based on some criteria.