The solubility of ammonia in ethanol was measured by a static analytic method. The total pressure is up to about 0.4 MPa, and temperature ranges from (277.35 to 318.25) K. The relationship between the partial molar volume of ammonia infinitely diluted in ethanol and temperature is obtained by measuring the density of (ethanol + ammonia) solution. The experimental results are used to determine the (molality scale based) Henry's constant of ammonia in ethanol, where the activity in the liquid phase is calculated by applying the molality scale based Gibbs excess energy model of Pitzer.