In order to solve the problem of dust pollution during road construction, an environmental friendly dust suppressant for road construction was prepared using water soluble starch, seaweed extract and hydroxypropyl methylcellulose as raw materials. To simulate the actual application of the dust suppressant, the prepared dust suppressant was diluted by different times and then sprayed on the dust samples. The moisture retention, moisture absorption, wind erosion resistance of the dust samples were tested. The results show that the moisture retention and moisture absorption of the dust sample maintain about 4.5% and 2.2%, respectively, 20 hours after sprayed by double diluted solution. After eroding by 10 m/s wind, the wind erosion rate is only 2.742%, and the viscosity and surface tension are 12 mPa·s and 46.90 mN/m, respectively. Compared with the dust sprayed with water, the dust sprayed with dust suppressant has more oxygen-containing functional groups and its hydrophilicity increases. After sprayed with double diluted dust suppressant, the dust sample has good adhesiveness.