Abstract: Phosphate is one of inorganic nutrients required by plants. Yields of crops were always affected by phosphate starvation. Study what happened in plants under the condition of phosphate starvation will help cultivating low-phosphate-resistant crops. Comparison wild-type Arabidopsis and phosphate-sensing mutants is an important way to research plant’s reactions to phosphate limitation. Finding right screening method is the key step to select phosphate-sensing mutants. On the vertical placement agar plates with normal phosphate concentration, the root of Arabidopsis was oriented to the earth. The root has many large curves. While on the phosphate-starvation agar plates, the root was nearly vertical. Using this phenomenon, we had selected a putative phosphate-sensing mutant. This mutant has short and vertical root on the phosphate normal agar plates. As no similar paper had been reported, this mutant may be a new phosphate-sensing mutant.