虚拟运行系统 (Virtual Execution System) 是一个可运行受管理代码 (Managed Code) 的运行环境，它提供了运行受管理代码所需要的内置数据型别 (data type) 以及假定的机器型态与状态设置、流程控制与例外处理等参数。

它提供了 MSIL 程序指令所需要的支持。

The Virtual Execution System (VES) is a run-time system of the Common Language Infrastructure CLI which provides an environment for executing managed code. It provides direct support for a set of built-in data types, defines a hypothetical machine with an associated machine model and state, a set of control flow constructs, and an exception handling model. To a large extent, the purpose of the VES is to provide the support required to execute the Common Intermediate Language CIL instruction set.