Abstract: Secondary ion mass spectrometry (SIMS) is a powerful surface analysis technique， and which was used in many fields. This paper reports a new type of the primary ion optics of SIMS, which consists of two ion condenser lens. It can be used to accelerate and focus the primary ions effectively, and produces a stable primary ion beam with adjustable energy in the range of 0－5 keV. Furthermore, by changing the voltage distribution at the two lens, this ion optics can be switched between two different focusing patterns and form two kinds of ion beams. The experimental results show that the primary ions produced using electron impact (EI) can be focused to around 20 μm in diameter with the ion current density of 503.2 mA/cm².