A urodynamic monitoring system and a drainage monitoring control unit are provided. The urodynamic monitoring system includes a drainage monitoring control unit and a monitoring host that is provided with a mainboard, a control component, and a weighing component, where the drainage monitoring control unit is formed by sequentially connecting a front drainage pipeline, a monitoring controller, a rear drainage pipeline, a urine collection bag, and the front drainage pipeline is provided with a first three-way valve communicated with air. When using this system, the first three-way valve communicated with air may be disposed on the front drainage pipeline, air pressure on a bladder is measured by switching a working state of the first three-way valve, and an accurate value of intravesical pressure is obtained by subtracting the air pressure on the bladder from pressure of urine in a monitoring control cavity.