A grip detection system of a steering wheel for an autonomous vehicle, may include an autonomous driving portion which autonomously drives a vehicle; a contact detector which is mounted on a steering wheel of the vehicle, and detects a change in capacitance due to contact between a driver and a steering wheel; a control portion which determines that the driver contacts with the steering wheel if the change in capacitance is received from the contact detector, and generates a warning signal when determining that the driver does not contact with the steering wheel if the change in capacitance is not received from the contact detector; and an output portion which receives the warning signal, and outputs the warning signal to outside.