The invention discloses a mobile terminal and a design method of an operation and control system thereof, the mobile terminal comprises a machine body and an embedded central processing unit, wherein a back surface touch panel is mounted on the back surface of the machine body, and three-state buttons are respectively mounted in lower middle positions on two sides of the machine body; and the embedded central processing unit is the embedded central processing unit equipped with the operation and control system including finger action semantic recognition, a virtual keyboard and an input method. The design method comprises the steps of designing the shape of the machine body, designing the finger action semantic recognition under the support of an algorithm of the operation and control system and designing the virtual keyboard and the input method in the operation and control system. The invention designs the back surface touch type mobile terminal with natural operation and control concept, thereby realizing the purposes of maximizing the liberation of a front surface touch screen, easily realizing operation and control, in particular to text input by single hand, improving the intelligent operation and control based on full combination of system software algorithm, software and hardware, leading the operation to cater for habitual thinking and natural reaction of a user, and being suitable for long-time use.