In this paper, we present a collaborative visualization environment(COVE). Our COVE provides not only collaborative but also paralleled computing environments based on distributed object model at once. It is built as a collection of concurrent objects which interact each other and consist of two types of objects : collaborative object and application object, which are used to construct collaborative and paralleled computing environments respectively. Collaborative objects enable COVE to execute various collaborative functions, while application objects enable it to execute various visualization modes in a parallel computing environment. COVE provides a flexible and extensible framework by plugging the proper application objects into COVE, and making them interact with one another through collaboration objects. COVE is built on DOVE(Distributed Object-oriented Virtual computing Environment), a new parallel programming environment based on distributed object model. In DOVE, virtual environment is constructed as a collection of concurrent objects, each of which has its own computing power, interacts with one another by remote method invocation and those objects can be handled as the same way as local objects. Also, heterogeneity, object group, multiple method invocation to object group, object life management,and naming service of object manager are supported to provide a transparent programming environment for parallel and distributed application. We designed collaborative work manager, session manager and application manager for managing cooperative work and ray casting algorithm is adapted for visualization algorithm. Our implementation result shows that various DOVE functionalities make COVE more extensible, scalable and efficient in distributed computing environment.