Abstract: Studying the high frequency properties of serpentine circular groove guide slow wave structure (SWS), the dispersion curves and interaction impedance are obtained by theoretic analysis and numerical computation. It is analyzed that the change of the structure parameter affects dispersion properties and interaction impedance. It shows that, dispersion property weakens and interaction impedance increases as the pitch L decreases. Though dispersion property weakens as the length of straight guide H increases, the interaction impedance still decreases. Therefore, short period is in favor of improving the high frequency properties of serpentine circular groove guide slow wave circuit, whereas the low interaction impedance of the circuit, interaction impedance can be improved by decreasing H pro