A smokeless flux has been developed, with 250 g/L ZnCl2 + 20 g/L SnCl2 + 12 g/L CeCl3 +10 g/L NaCl+20 g/L KF +1g/L surface active agent in the formula, with 60 ℃ the fluxing temperature, 30 s the fluxing time, (450± 10) ℃ the dip temperature, 30 s the dip plating time in the plating process. A comparison has been made between the smokeless flux and the traditional flux, and a thorough observation has been made of the flux salt film morphology under the metallographic microscope and SEM, and a research has been conducted on the casing quality and the coating thickness and structures, followed by a testing of the corrosion resistance of the coatings with the aid of polarization curves and immersion test results. The experimental results show that, compared with the traditional flux, the smokeless flux has a more homogeneous and thicker distribution of salt membrane. The casting surface is free of leakage and smooth with both fluxes, with a decreased coating thickness and a more compact alloy coating for the smokeless flux. With the phase layer suppressed to a certain extent, its coating corrosion resistance has increases by about 25%~50% compared with the traditional flux.