The present invention relates to a switch capacitance second order band-pass filter which is provided with four programmable capacitors, if two integrating capacitor values of the filter are C1 and C2 respectively, capacitance values of four programmable capacitor are Alpha1C1, Alpha2C2, Alpha3C1, Alpha4C2, wherein, Alpha1-Alpha4 satisfies: Alpha1=Alpha2=Omega0T, Alpha3=1/Q, Alpha4=KT. Wherein, Omega0 is filter center frequency, Q as filter figure of merit, and K as filter gain coefficient. Thereby the three parameters can be adjusted independently. The present invention also puts forward continuous time RC structure with above band-pass filter and difference structure.