Abstract: In the course of the floating seeding, an advanced seedling techniques, the strict disinfection of the float trays, plastic, clipping appliance and operation is the key link for breeding anosis and strong seedling. To use disinfector more rationally to tobacco production, 10 active disinfector was studied of their inhibition against Phytophthora nicotianae. The results indicated that great majority disinfector can inhibit the growth of Phytophthora nicotianae, including copper sulfate, American disinfector, 0.6%“Jun Du Jing”, 7% available chlorine sodium hypochlorite, 24%“Du Xiao”, 40%“Yu Bao”, 10% chlorine dioxide, sodium phosphate，however Potassium permanganate, 30% available chlorine bleaching powder had no inhibition on the growth of Phytophthora nicotianae hyphae and sporangium.