To　increase　the　jetting　frequency　of　our　previously　home-built　pneumatic　microdrop-on-demand　system,　the　influences　of　chamber　volume　and　solenoid　valve　control　on　the　maximum　stable　jetting　frequency　were　studied.　The　key　components　of　the　system　included　a　chamber,　a　tiny　orifice　of　micron　dimension,　a　gas　path　with　a　high　speed　solenoid　valve　and　a　venting　tube,　and　a　photographic　system　used　for　evaluating　the　uniformity　and　consistency　of　the　micron　size　droplet.　A　pressure　pulse　was　created　within　the　chamber　via　opening　the　solenoid　valve　for　a　brief　period　of　time.　The　liquid　was　pushed　out　through　the　nozzle,　generating　a　droplet.　The　gas　was　then　released　through　the　venting　tube,　recovering　the　system　back　to　equilibrium.　Results　show　that　reducing　the　volume　of　the　chamber　and　reducing　the　opening　time　can　significantly　improve　the　highest　stable　jetting　frequency　of　the　system.　The　speed　of　the　droplet　shows　a　trend　of　increasing　as　the　jetting　frequency　becomes　higher.　For　shorter　＂on＂　period　of　the　valve,　the　diameter　of　the　droplet　shrinks,　and　it　can　effectively　improve　the　control　of　the　system　for　precision　samples.　©2019,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.