In order to overcome the disadvantages of thermal expansion measurements using small samples, such as 10mm×50mm, for refractories with aggregates larger than 20mm, a new apparatus and method were developed by Wuhan University of Science and Technology for the thermal expansion determination of refractories using large samples. Thermal expansion determination of large refractory samples, such as 40mm×40mm×160mm, can be finished by this new apparatus up to 1600°C. During the process of thermal expansion measurement by this new apparatus, the temperature difference along the length of large refractory sample with large aggregates can be observed by three thermocouples, which were inserted into sample. Determination was done when the whole sample is the same temperature or in the permissible temperature range. Results comparison between this new apparatus and calibrated model 1161V dilatometer produced by ANTER Corporation show that developed apparatus has good accuracy.