To assess students’ understanding of heat energy, the students were asked to compare the amount of heat energy of two objects at different temperatures to specify the factors of heat energy. Two objects are made of the same material but have different mass. Only 10% of the students held correct understanding that heat energy is depended on not only specific heat capacity and temperature, but also the mass of the objects (Heat as intensity). While 57% of the students thought that the object that had higher temperature would have more heat energy and 24 % of the students thought that heat energy is depended on the specific heat capacity of objects only. By changing the situation, students were asked to compare the amount of heat energy of two objects at 0C in the freezer. The objects are made of the same material but have different sizes. The results showed that 23% of the students held correct understanding that heat energy is depended on not only specific heat capacity, but also the mass of the objects. However, 20% of the students thought that two objects that had different sizes (both were the same materials at 0C) would have the same heat energy because both of them were in the same state. Twenty nine percent of the students thought that heat energy is depended on the specific heat capacity of objects, so that if both of them were made from the same material, they would have the same heat energy. Interestingly, 12% of the students still thought that specific heat capacity depended on the size of objects.