What is the main function of the lymphatic system? Lymphatic drainage from a capillary bed to the venous circulation. What is the main function of the lymphatic system? Lymphatic drainage from a capillary bed to the venous circulation. The lymphatic system makes blood cells through a process known as hematopoiesis. The lymphatic system transports blood and lymph throughout the body. The lymphatic system produces high fluid pressures to assist in lymph motion. The lymphatic system returns leaked fluid and plasma proteins that escape from the bloodstream to the blood.