An apparatus for detecting capacitance, comprising: a signal driving circuit, configured to periodically charge and discharge at least one capacitor to be detected; a conversion circuit, configured to convert a capacitance signal of the at least one capacitor to be detected into a voltage signal; and a cancellation circuit, configured to cancel initial capacitance of the at least one capacitor to be detected, so that the voltage signal is associated with a capacitance change of the at least one capacitor to be detected; wherein the conversion circuit comprises a first feedback capacitor, the cancellation circuit comprises a first adjustable capacitor, and is configured to carry out the following steps: at a first time, a first capacitor to be detected is charged, at a second time, charges on the first capacitor to be detected are transferred onto the first feedback capacitor and the first adjustable capacitor, at a third time, the first capacitor to be detected is shorted to ground, at a fourth time, charges on the first adjustable capacitor and the first feedback capacitor are transferred onto the first capacitor to be detected, and in an initial state, a magnitude of capacitance of the first adjustable capacitor is adjusted to make an output based on the voltage signal to be zero, so as to cancel the initial capacitance, so that when capacitance of the first capacitor changes, an output based on the voltage signal represents a capacitance change of the first capacitor to be detected. a signal driving circuit, configured to periodically charge and discharge at least one capacitor to be detected; a conversion circuit, configured to convert a capacitance signal of the at least one capacitor to be detected into a voltage signal; and a cancellation circuit, configured to cancel initial capacitance of the at least one capacitor to be detected, so that the voltage signal is associated with a capacitance change of the at least one capacitor to be detected; wherein the conversion circuit comprises a first feedback capacitor, the cancellation circuit comprises a first adjustable capacitor, and is configured to carry out the following steps: at a first time, a first capacitor to be detected is charged, at a second time, charges on the first capacitor to be detected are transferred onto the first feedback capacitor and the first adjustable capacitor, at a third time, the first capacitor to be detected is shorted to ground, at a fourth time, charges on the first adjustable capacitor and the first feedback capacitor are transferred onto the first capacitor to be detected, and in an initial state, a magnitude of capacitance of the first adjustable capacitor is adjusted to make an output based on the voltage signal to be zero, so as to cancel the initial capacitance, so that when capacitance of the first capacitor changes, an output based on the voltage signal represents a capacitance change of the first capacitor to be detected. at a first time, a first capacitor to be detected is charged, at a second time, charges on the first capacitor to be detected are transferred onto the first feedback capacitor and the first adjustable capacitor, at a third time, the first capacitor to be detected is shorted to ground, at a fourth time, charges on the first adjustable capacitor and the first feedback capacitor are transferred onto the first capacitor to be detected, and in an initial state, a magnitude of capacitance of the first adjustable capacitor is adjusted to make an output based on the voltage signal to be zero, so as to cancel the initial capacitance, so that when capacitance of the first capacitor changes, an output based on the voltage signal represents a capacitance change of the first capacitor to be detected.