Wheat substitution lines between Chinese Spring and Synthetic 6x under the treatments of phosphorus deficiency stress and phosphorus normal (control) were studied to locate the gene controlling yield traits. Several yield components such as grain weight per spike, 1000-grain weight and kernel number per spike were measured. The results showed that the genes promoting grain weight per spike might be located on 6A, 7A , 1B, 2B, 3B, 4B , 5B, 6B, and 7D chromosome of Synthetic 6x, and that the genes promoting 1000-grain weight might be located on 2A, 5a, 6 a, 3B, 5B, 6B, 7B, 5D and 7D chromosome, and that the genes promoting relative kernel number per spike might be located on 6A, 7A, 1B, 3B, 2D and 7D chromosome under the low-phosphorus stress. It is concluded that chromosome 3B and 7D of Synthetic 6x probably carry related genes tolerating low phosphorus stress.