The velocity, temperature and humidity in the chamber of the Continuous Flow Streamwise Thermal-Gradient CCN Counter manufactured by DMT were successfully simulated using the computational fluid dynamics software ANSYS FLUENT. With velocity of 0.0164, 0.0185, 0.0205, 0.0226, 0.0246 m/s and temperature settings of ΔT 2, 8 and 17 K, the influence of velocity and temperature on the flow were tested. Results show that, velocity and temperature setting of CCNC influenced both velocity field and temperature field. When ∆T=8 K, v=0.0205 m/s, the supersaturaiton on the centerline was about 0.27%. Supersaturation in the CCNC chamber was simulated successfully.