This study was conducted to investigate the characteristics of role of transport on aerosol concentration at Crate Lake, Oregon USA for 1988.3～1999. 5. The IMPROVE program is a cooperative measurement effort governed by a steering committee composed of representatives from USA federal and regional-state organizations. Also IMPROVE sampler is designed to obtain a complete signature of the composition of the airborne particles affecting visibility. According to 10-day backward isentropic trajectory analysis, the frequency of local, marine and Asian trajectory showed 33.1%(335 cases), 47%(478 cases), 5.2%(53 cases) respectively. The monthly variation of nss SO42-, nss S, NO3-, K and C showed the double peak pattern, high in April～May and August～September and showed the lowest concentration in Winter. The other constituents concentration except for Cl-, Na, Mg was high in local trajectory than marine trajectory. A ratio nss SO42- to SO42- was 90.5% in marine trajectory and 98% in local trajectory. It suggest that the aerosol in Crater Lake was effected by salt. The annual mean concentration of nss SO42- and nss S decreased but the the springtime concentration increased.