A nanofocusing element based on subwavelength microcavity is proposed and demonstrated. Excited surface plasmons wave participates in interference in the microcavity, which results in a standing wave. Subsequently, the energy is coupled into the taper structure, and gives rise to a nanofocusing spot whose FWHM is about 100nm. It is found that the localized energy can be modulated by changing the length of surface plasmon microcavity. By using electromagnetic field simulation software FDTD, we characterize the intensity distribution pattern and open out the inner working principle of the element.