Lodging is one the important factors that limit rice yield and reduce rice grain quality. Lodging made the process of conveying dried substances for making grain be obstructed, the panicles were sunk into water, decomposed and caused difficulties for harvesting. The study was conducted aiming to define the concentration of Paclobutrazol (PBZ) optimal with the growth and hardness of rice, helping with limiting lodging and increasing the yield. The experiment was conducted in the Summer-Autumn crop in Thoai Son District, An Giang Province. The experiment was carried out in Randomized complete block design (RCBD) with six treatments (0 (control), 25, 50, 75, 100 and 125 mg/L) and four replications per treatment. The results showed that the treatment of Paclobutrazol at concentration of 50 mg/L induced the rice with increasing the number of tillers and stem’ hardness, number of panicle/m², filled grain ratio and yield (5,85 tons/ha, increasing 8,13 % compared to the control).