Abstract: This paper chose KI as the most appropriate contrast agent for masson pine seeds. The x-ray contrast method proceeded as follows;The seeds were soaked in tapwater at 25℃ for 12h, and superficially dried, then steeped in 40% solution of KI for 1.5h. After washing in running water for 2min, the seeds were dried at 70℃ for 2h. The dried seeds were radiographed under the following conditions;voltage=20 kV, electric current=3mA, exposure time=60sec, focus-film-distance=25cm. The unim-pregnated normal seed was considered as viable seed for calculating germi-nability. The germinability (x) of 41 seed samples was very close to the germination percent (y). The relationship was y=-4.7+1.07x, r=0.96.