The invention relates to a control method for the thermal deformation compensation of a ram of a numerical control machine and a device for implementing the same, which mainly solve the problem of machining error caused by flexible deformation due to the change of the ram of the numerical control machine with the change of temperature. The control method is characterized in that: a micrometric displacement detection device which has low thermal expansivity and is fixed on the ram is adopted, and one end of a displacement reference measuring rod in the micrometric displacement detection deviceextends freely and forms a thermal displacement measuring factor with a micrometric displacement sensor; a thermal deformation flexible signal, which is detected by the micrometric displacement detection device, of the ram is processed and converted by an embedded compensator to form two paths of orthogonal pulse signals; the orthogonal pulse signals are generated by a method of controlling a quarter of the period of the signals, and is inputted to a numerical control system by a hand-held unit interface of the numerical control machine; and the system performs real-time compensation by calling a fine motion differential analyzing function. After the control method is used, the machining error caused by thermal deformation in the ram of the numerical control machine can be reduced greatly, so the control method has the excellent economic and social benefit.