根据生理学原理对影响手计时准确性的原因进行了分析。认为造成开表不准的主要原因是手计时者“应答时个体差异”，造成停表不准的主要原因是“无依据停表”和“预测不准”。文章提出用“应答时筛选法”缩小应答时个体差异，提高开表的准确性，用“停表时机表”增加停表的精确度。文章对以往手计时法的概念进行了论证，认为其只能称为“不完整计时”和“定性计时”。建议以“应答时修正值”加以修正，以实现手计时的完整性和定量化。从而在本质上提高手计时的可信度和准确性。 According to the physiological principle of hand timing accuracy of the reasons were analyzed. It is considered that the main reason for causing the openness to be not accurate is that the timekeeper “responds to the individual differences”. The main reasons causing the stoppage of the stoppage are “no basis stopwatch” and “no prediction”. The paper proposes to use the “screening method of response time” to narrow the individual differences in response and improve the accuracy of the open table, and increase the accuracy of the stop watch with the “stop timing table.” The article argues that the concept of hand-timing method in the past is only called “incomplete timing” and “qualitative timing.” It is suggested to amend “response time correction value” to achieve the integrity and quantification of hand timing. Thus essentially increasing the credibility and accuracy of hand timing.