Research on piezoelectric unimorph actuators has been intensively increased during the past decade due to the wide applications of this actuator type in aerospace, vibration control, biomimetic robots, artificial muscles… Most analyses focused on the design performance with load-free actuating condition. Loading performance has not been considered adequately yet though in real application the actuators always work under certain carrying load. This paper introduces the measuring system, the experimental setup and presents the observed loading performance of the actuators with center load. Two typical kinds of piezoelectric unimorph actuator, LIPCA-C3 and THUNDER, are investigated. The numerical analyses are also conducted to illustrate the loading behavior of these devices. Some remarks and suggestions for future research activities are drawn.