A method of blind spot detection is provided. The method of blind spot detection is used for a vehicle including a first vehicle body and a second vehicle body dragged by the first vehicle body. The method of blind spot detection comprises the following steps: obtaining a turning angle information of the second vehicle body relative to the first vehicle body by a first sensor while the vehicle is moving; determining a predetermined information related to the vehicle and/or a second sensor; dynamically defining a blind spot area around the vehicle according to the turning angle information and the predetermined information; and receiving a sensing signal regarding an object around the vehicle from the second sensor to determine whether the object is located in the blind spot area.