A flow control mechanism and a system comprising the mechanism, specifically relating to a microflow control mechanism and system. The mechanism comprises a base and a constant volume mechanism. The base and the constant volume mechanism are dynamically connected to form two or more relative activity states, comprising a first relative state and a second relative state. A fluid input end and a fluid receiving end are provided on the base. The constant volume mechanism is provided with a constant volume pipeline. In the first relative state, the fluid input end communicates with the constant volume pipeline. In the second relative state, the constant volume pipeline communicates with the fluid receiving end. The microflow control mechanism and system can achieve precise micro-scale fluid flow control, and have a simple structure.