In this paper, punching shear test of flat plate reinforced by plates with openings has performed. And compared critical section of ACI 318, BS 8110, and Eurocode 2. Non-reinforced specimens and specimens that reinforced by GFRP plates with openings are manufactured. Shear reinforcement spacing was used as parameter for specimens reinforced by GFRP plates. Crack pattern showed that critical section increased as shear reinforcement spacing increased compared to critical section of ACI 318, BS 8110, and Eurocode 2. Critical section calculated by ACI 318 was the smallest predicted section, and sections calculated by BS 8110 and Eurocode 2 are larger predicted section.