The invention discloses a constant speed cruise control system based on a mobile phone and control method thereof. The constant speed cruise control system based on the mobile phone comprises a mobilephone system and a constant speed cruise system; and the mobile phone system and the constant speed cruise system are connected with each other by using a Bluetooth communication mode. The constant speed cruise control system based on the mobile phone can improve the constant speed cruise system by using the mobile phone so that functions of a self-adaptive constant speed cruise system are realized; by using a GPS navigation system of the mobile phone, real-time positioning function, traffic jam status monitoring function and speed limiting monitoring function of an automobile can be realized; and mostly, automobiles with low configurations can be remodeled into automobiles with self-adaptive cruise functions at a low cost.