The work aims to take the cigarette packet as the research object to determine its longitudinal and lateral indentation stiffness according to YC/T 330, and analyze the measurement uncertainty value introduced by the crease straightener, size deviation of specimen cutting and measurement repeatability, so as to obtain the measurement uncertainty of the indentation stiffness of cigarette packet. The standard uncertainty value, also known as class A uncertainty, was obtained after the standard deviation was calculated by 10 independent repeatability tests on indentation stiffness. Then, the uncertainty caused by measurement instrument and sampling size deviation was calculated according to the evaluation method of class B uncertainty, and the uncertainty of class B was obtained. The synthetic uncertainty was calculated. Finally, the expansion uncertainty was calculated. According to YC/T 330, the expansion uncertainty of cigarette packet A was Ulongitudinal=(83.1±6.22)g, k=2; Ulateral=(59.7±4.20)g, k=2. According to the evaluation results, the influence components on the uncertainty range from large to small are: size deviation of specimen cutting, measurement repeatability and calibration parameters of crease straightener.