In these days, fims have recognized the potential and the importance of electronic commerce to survive in this increasingly complex and competitive market. Electronic commerce can be used to create and enhance competitive strategies by all types and sizes of firms. Today all types of firms are squaring off for a dominant position in a virtual market. However firms should carefully consider various factors such as the size of a firm, its access to resources, and the industry in which it competes. The resource-based theory is one of attempts to explain how firms acquire a strategic advantage emphasizes the availability of various internal resources for sustainable competitive advantage. The resource of the dot.com was usually augmented by on or more of a network of joint ventures, strategic alliances and venture capital consortia, but the surviving dot.coms are usually led by new and more realistic wealth creators. This paper integrates environment, generic strategies, and the resource-based perspective on performance in online firms. More theoretically the results will imply the environment factors and the resource factors which can influence the strategic choices and the selected strategies make a direct impact on the performance. And also the resources of firm are another in determining performance. And the practically, managers in online firms must consider firms assets and environment simultaneously to firm success.