Abstract: The primary features, seeding rate and main dominant factors of the liquid carbon dioxide seeder are described.The phase, particle shape and size spectrum of particles from the seeder are measured by probes of such instruments as FSSP-100, 2D-C, threefold drop-size meter and visibility detector.Measurements show that effluents from the seeder are a mixture of vapor, liquid and solid substances of CO₂.The lifetime of liquid and solid particles at 10^-1to 10²μm in diameter ranges over 10⁰to 10¹second.The mass per unit volume of the effluent reaches 3.6 g·m^-3.These measurements provide a reliable basis for liquid carbon dioxide as catalyst in cold clouds, which is a catalysis technique suitable for artificial rain enhancement in warmer strati form clouds in our country.