In order to research on the air pollutants' long-range transportation in North China, aerosol samples were collected with Andersen cascade sampler at the summit of mount Tai during June 2006, in Shandong Province. The water soluble ionic concentrations were analyzed by IC. It shows that there are three types of size distribution: 1) ions whose mass resided mainly within the accumulation mode with the peak at 0.43-0.65 microm (SO4(2-), NH4+, K+); 2) Ions whose mass resided mainly within coarse particles with the peak at 4.7-5.8 microm (Ca2+, Mg2+); 3) Ions which were two modes with the peak at 0.43-0.65 microm and 4.7-5.8 microm (NO3-, NO3-,Cl-). The mass median diameter of SO4(2-) with high concentration is between 0.5 microm and 0.8 microm, and belongs to the "drop mode". The concentration of ions such as SO4(2-), NO3-, NH4+ and K+ has a huge variety and the sulfate has the most great variety with the lowest concentration which is 4.0 microg x m(-3) and the highest concentration which is 42.3 microg x m(-3). The ions (SO4(2-), NO3-, NH4+) reach the high value when the humid air mass comes from the south.