A mattress system devised to achieve a function of automatic detection, mainly including a mattress having a simple structure a control unit equipped with a unique user interface for caregivers to simultaneously adjust three major functions, namely, therapy mode, therapy intensity and comfort level and a connection pipe for supplying air and power. The system is further provided with a built-in auto-setting function to sense the body characteristics of the patient lying on the mattress and determine an effective supporting pressure range for the patient. By detecting a pressure difference representing the body characteristics of the patient lying on the mattress and comparing with the data stored in a built-in database, the system can always provide the patient with not only a well-proved therapeutic effect through the auto-setting function, but also an adjustable comfort level on the patients request through the user interface.