A control circuit for detecting a capacitive change of a touch panel, comprising: a signal-detecting circuit for charging a sensing wire of the touch panel to obtain a voltage intensity signal corresponding to the sensing wire; an intensity/frequency conversion unit for converting the voltage intensity signal into a frequency signal, the frequency of which is proportional to the level of the voltage intensity signal; and a frequency-analyzing unit for analyzing the frequency signal to obtain a signal amount of the corresponding sensing wire, wherein the signal amount corresponds to a capacitance of an equivalent capacitor (Cx) sensed by the corresponding sensing wire; wherein the signal-detecting circuit is a capacitance-detecting circuit for providing a power source to charge an equivalent capacitor of the sensing wire, and correspondingly providing the power source having the same magnitude to charge an internal capacitor so as to obtain the voltage intensity signal; and wherein the voltage V out of the voltage intensity signal generated by the capacitance-detecting circuit is expressed by the following formula: V out ≈ L a W b W a L b V DD − V T C X C in which L a is the gate length of a transistor a of the capacitance-detecting circuit, W a is the gate width of the transistor a, L b is the gate length of a transistor b of the capacitance-detecting circuit, W b is the gate width of the transistor b, V DD is the supply voltage, V T is the critical voltage of the transistor, C X is the sum of the equivalent capacitance of the sensing wire and a stray capacitance of the circuit board of the control circuit, and C is the internal capacitance of the capacitance-detecting circuit. a signal-detecting circuit for charging a sensing wire of the touch panel to obtain a voltage intensity signal corresponding to the sensing wire; an intensity/frequency conversion unit for converting the voltage intensity signal into a frequency signal, the frequency of which is proportional to the level of the voltage intensity signal; and a frequency-analyzing unit for analyzing the frequency signal to obtain a signal amount of the corresponding sensing wire, wherein the signal amount corresponds to a capacitance of an equivalent capacitor (Cx) sensed by the corresponding sensing wire; wherein the signal-detecting circuit is a capacitance-detecting circuit for providing a power source to charge an equivalent capacitor of the sensing wire, and correspondingly providing the power source having the same magnitude to charge an internal capacitor so as to obtain the voltage intensity signal; and wherein the voltage V out of the voltage intensity signal generated by the capacitance-detecting circuit is expressed by the following formula: V out ≈ L a W b W a L b V DD − V T C X C in which L a is the gate length of a transistor a of the capacitance-detecting circuit, W a is the gate width of the transistor a, L b is the gate length of a transistor b of the capacitance-detecting circuit, W b is the gate width of the transistor b, V DD is the supply voltage, V T is the critical voltage of the transistor, C X is the sum of the equivalent capacitance of the sensing wire and a stray capacitance of the circuit board of the control circuit, and C is the internal capacitance of the capacitance-detecting circuit.