The solubility and surface activity of the collector, octadecylamine (ODA), in water, saturated KCl and saturated KCl-MgCl2, respectively, were measured at 5、15 and 25 °C. The experimental results showed that critical assemble concentrations (cac) of ODA was 4.65×10-4 mol/L at 25 °C without added salt, which was 2.19×10-5 mol/L in saturated KCl and 8.63×10-6 mol/L in saturated KCl-MgCl2. Under the same temperature, solubility and surface activity of ODA both reduced in saturated salt solution compared with those in water. In addition, the surface tension and turbidity increased with the temperature decreased, with decrease of solubility and surface activity , resulting in the reduction of the saturation surface excess concentration and the increasing of minimum area. However, the effect of temperature on cac was much less obvious.