There is often a misconception about the different structures found along the Great Wall of China. Many people mistakenly refer to all the watchtowers as beacon towers, but this is not entirely accurate. The functions of beacon towers and watchtowers are actually quite different. By comparing the architectural forms and locations of the existing beacon towers and watchtowers, significant differences can be observed. Watchtowers served as lookout posts and fortresses where soldiers could be stationed, weapons and supplies stored, and battles fought against invading enemies. Consequently, areas with flat terrain and vulnerable to attacks were more likely to have multiple watchtowers constructed for enhanced defense. On the other hand, the primary role of beacon towers was to provide early warning signals and timely alerts to the frontier passes and the interior. To fulfill this duty effectively, beacon towers needed to be situated in elevated locations with good visibility, allowing them to spot enemy movements from a greater distance. As soon as the dust from enemy cavalry emerged on the horizon, the beacon fires would be lit, notifying the border guards to be on high alert. Therefore, the crucial prerequisite for selecting beacon tower locations was to ensure a commanding view, enabling the earliest possible detection of enemy activities.

Sometimes, the most suitable vantage point was far beyond the actual Great Wall. In such cases, the beacon towers had to be constructed outside the wall, isolated and vulnerable to potential enemy attacks. These protruding towers, often known as "outpost towers," were indeed dangerous, as they faced the risk of being ambushed and destroyed by the enemy. In border regions, they were also referred to as "border outpost towers."

There were also beacon towers built directly on the Great Wall, known as "border towers." Similar to other beacon towers, their primary objective was to provide elevated observation points. Consequently, the selection criteria focused on higher elevations. In contrast to the hollow watchtowers constructed in a continuous line, these border towers were fewer in number but stood at higher altitudes.

Additionally, if there were suitable locations within the Great Wall that were higher than the wall itself, beacon towers would be constructed there. These towers not only served as lookout points but also facilitated the transmission of alerts from the border towers. The areas within the Great Wall are often metaphorically referred to as the "interior". These types of beacon towers are known as "interior link towers". Generally, they were numerous, extending all the way to the inland regions, and it was through these interconnected towers that cities and central institutions located far from the border could quickly receive warnings, grasp enemy situations, and respond accordingly.