Chemical seed dressing is an effect ive method to control phytophthora root rot of soy bean at presenttime .58 %WP Ridomil-MZ and 72 %WP CURZATE -M8 were screened in laboratory and field to cont rolphy tophthora roo t rot of soybean .The cont rol effect of the two chemicals w as much better .The propo rtion of chemicals to seeds w as 3 to 1 0 0 0 .The ef fect of cont rol w as over 8 5 % , yield w as increasedover 12 % and safe to soybean .