Determination has been made of the ice nucleation of AgI with rainmaing and hail suppression rocket JFJ. A preliminary study suggests that 4 grams or 2 grams of AgI is desirable. The rate of ice nucleation is 1-2 orders higher than that with shell 37 and one order higher than that with rocket JBR-56 at temperature -16℃ or more. The number of AgI particles formed after the explosion of rocket JFJ from electronic microscope analysis is 1.7×10¹⁶g^-1, corresponding approximately to actual determination.