Excretory system and urinary system are both working to remove waste in the human body. but technically, urinary system is part of the excretory system. The excretory system includes the kidney organ which is the main and the most important organ of the urinary system, another part of the excretory systems are the large intestine and the lungs. on the other hand, urinary system aside from kidney includes ureters, urinary bladder and the urethra. when the human body produces waste products, both the excretory and the urinary work together to remove these waste products from the human body.