The single pile static load test is the core method for evaluating the bearing capacity of a single pile, and reasonably determining the loading amount of the static load test is crucial for ensuring the safety of the pile foundation. This article elaborates on the requirements for determining the loading amount of single pile static load tests in relevant specifications. Focusing on the applicability issue of the conventional loading amount, which is set as twice the characteristic value of the single pile bearing capacity, it conducts stress analysis on pile foundations under four special conditions. Combined with specific cases, research is carried out, and finally, suggestions for determining the loading amount of single pile static load tests under the four special conditions are proposed. The study shows that the conventional method of determining the loading amount as twice the characteristic value of the single pile bearing capacity will reduce the safety degree of engineering piles during the service stage under the special conditions in this paper. The proposed study suggestions can provide reference basis for single pile static load tests under similar special conditions.