This paper has studied the technological process for preparation of grain potassium picrate (PK), which can meet the requirements of production in batches. In this study, the technological conditions for preparation of grain PK, i.e. the rescrystallization of PK, the reaction of picric acid with potassium hydroxide, the granulation of PK etc. were optimized. A number of properties of grain PK, including thermal stability, sensitivities for heat, impact, flame, friction and electrostatic spark, compatibility, heat of combustion, and detonation volume etc. were measured and evaluated. At present, the preparation has been scaled-up to several hundred grams. The product has already been applied to many ignition devices in the military industry.