The V model of what? "The V model" by itself doesn't mean anything. If you're talking about software development, read this.
It is a product-development process originally developed in Germany for government defense projects and it has become a common standard in software development. V-Model has gained acceptance because of its simplicity and straightforwardness. However, some developers believe it is too rigid for the evolving nature of IT (information technology) business environments.
The V-model represents a software development process (also applicable to hardware development) which may be considered an extension of the waterfall model. Instead of moving down in a linear way, the process steps are bent upwards after the coding phase, to form the typical V shape. The V-Model demonstrates the relationships between each phase of the development life cycle and its associated phase of testing. The horizontal and vertical axes represents time or project completeness (left-to-right) and level of abstraction (coarsest-grain abstraction uppermost), respectively.