Abstract: In this paper, finite element method was used to study the influence of specimen size on the restraint intensity of rigid butt-jointed cracking test specimen and variable restraint cracking test specimen. The results show that the restraint intensity increases with the increase of the specimen thickness. With the increase of the thickness from 20 mm to 50 mm, the restraint intensity increases from 14.87 kN/(mm·mm) to 20.72 kN/(mm·mm) for rigid butt-jointed cracking test specimen, and the restraint intensity increases from 10.46 kN/(mm·mm) to 16.23 kN/(mm·mm) for variable restraint cracking test specimen. For the 40 mm thick rigid butt-jointed cracking test specimen, when the width of the restrained specimen increases from 125 mm to 275 mm, the restraint intensity of the specimen decreases. However, with the width of the specimen increases further, the restraint intensity of the specimen does not change significantly. For the 40 mm variable restraint cracking test specimen, with the restraint specimen width from 125 mm to 575 mm, the restraint intensity shows a continuous downward trend.