The present invention discloses a driving circuit for electronic horn and a driving method for the electronic horn. The driving circuit includes an oscillating circuit, which generates a signal having oscillating frequency. Based on the signal, said driving circuit generates a driving signal to drive the electronic horn to produce sound. It is characterized in that said oscillating circuit includes a variable capacitor, and the oscillating frequency is changed by adjusting capacitance of the variable capacitor so as for the frequency of the driving signal to be consistent with working frequency of the electronic horn. The present invention overcomes the problem of mismatch between the frequency of circuit's driving signal and the horn's sounding diaphragm and horn's tone inflexion due to resistance change caused by vehicle vibration.