The goal of a software product line is to create a suitable platform for fast and easy production of software for same market segment. However, a software product line is limited because it needs to meet new stakeholder requirements either through upgrades or the introduction of new technologies. A Multi Product Line aims at deriving new software products from reuse of a set of features provided by several heterogeneous software product lines without modifying or altering the independent operation of the same. This paper presents a study about the application of Multi Product Lines in the software development process. It shows some domains that illustrate applications of multi product lines principle in the process and the product. Also, the main current challenges in applying multi product line in software engineering are described. This paper aims to show the importance and usefulness of applying multi product lines approaches in Software Engineering.