Embedded parallel λ/4(λ is the wavelength) open stub structure and its band stop properties were presented. Embedded open stub structure was applied to design a 3 order narrow band strip line band stop filter, which had the center frequency of 2.46 GHz, the stop band bandwidth of 50 MHz and the maximum elimination up to 60 dB. Compared with the traditional band stop filter with open circuited stubs, embedded open stub band stop filter was more compact in lateral dimension. Based on stepped impedance resonator (SIR) structure, another compact strip line band stop filter with the same target was designed. Compared with embedded open stub band stop filter, the longitudinal size of the embedded SIR band stop filter was reduced by about 17.5% with better harmonic suppression characteristics.