In this study, we developed a Particle Sampler for Aerosol Suspension (PSAS) to collect ambient PM2.5 directly as liquid suspensions. The PSAS operates at 50 L/min and contains a custom-designed PM2.5 inlet for particle pre-selection, followed by a saturation-condensation unit for condensational growth that enlarges fine particles to 2~5 μm droplets. The grown droplets are sequentially collected in a newly designed collection impactor into liquid suspensions. Laboratory evaluations indicate good collection efficiencies of PSAS for both polydisperse and monodisperse fine particles, showing that 85% of particles are effectively preserved into collected suspensions. Field evaluations suggest good agreements for analyzed chemical components (water soluble Fe (II) and Cr (VI)) of ambient PM2.5 between suspensions collected by PSAS and parallel filters. The reported PSAS can be used for long-term particle collections and online chemical and toxicological analysis of ambient PM2.5.