The followings are the notation supported by use case diagram.
| Name | Image | Description |
| UseCase |  | A UseCase is a kind of behaviored classifier, which represents a declaration of an offered behavior. It specifies some behavior, possibly including variants such as exceptional behavior and error handling, that the subject can perform by communicating with one or more actors. |
UseCase (caption
align bottom) |  | Another presentation of use case. The caption is put below rather than inside the ellipse shape. |
UseCase
(box shape) |  | Another presentation of use case. The use case is shown as rectangle with a small ellipse icon appear at the upper right hand corner of the rectangle. |
| Association |  | Association represents the collaboration between an actor and a use case. |
| Actor |  | Actor specifies a role played by human users, external hardware, or other subjects that interacts with the subject. |
Actor (box shape
with keyword) |  | Another presentation of actor. The actor is shown as rectangle with the keyword «actor» display at the top of the rectangle. |
Actor (box shape
with icon) |  | Another presentation of actor. The actor is shown as rectangle with a small stick man icon appear at the upper right hand corner of the rectangle. |
Actor (customized
shape) |  | Another presentation of actor. The actor is shown as customized shape. |
| System |  | System represents the boundary of the subject. |
| Include |  | Include is a directed relationship between two use cases, which implies that the behavior of the included use case is inserted into the behavior of the including use case. |
| Extend |  | Extend is a relationship between two use cases, which specifies how and when the extended use case insert the behavior defined in the extending use case. |
Extend (caption
align bottom) |  | Another presentation of use case. The caption is put below rather than inside the ellipse shape, while the extension points are still put inside the ellipse shape. |
Extend
(box shape) |  | Another presentation of use case. The use case is shown as rectangle with a small ellipse icon appear at the upper right hand corner of the rectangle. The rectangular presentation is much natural than ellipse when it involve a long listing of extension points due to the definition of a large number of extension points. |
| Dependency |  | A dependency is a relationship implying that a use case requires other another use case for its specification or implementation. |
| Generalization |  | A generalization relationship relates a more general use case and a more specific use case. |
| Realization |  | A realization relationship link up the specification and the implementation of that specification. |
| Collaboration |  | A collaboration is used to describe the structure of collaborating elements. |
| Note |  | A Note is a textual explication that can be attached to set of elements. |
| Anchor |  | An anchor is a connection between note and elements. |
| Constraint |  | A constraint specifies condition or restriction that expressed in natural language or machine readable language for declaring some of the semantics of an element. |
| Containment |  | A containment represents a contain relationship between package and members. |
| Package |  | A package groups elements and provide them with namespaces. |
