根据测量热扩散率的光声压电(PAPE)技术简化热弹理论，分析了该方法中样品厚度、热扩散率大小对测量结果的影响以及PAPE技术的适用范围。介绍了基于简化热弹模型理论的PAPE技术，得出了简化的光声压电信号幅度和相位与调制频率的相互关系; 根据PAPE技术理论分别对相同厚度不同材料热扩散率测量的灵敏度和不同厚度同一材料热扩散率的测量误差进行理论分析; 通过实验分别对厚度约为2 mm的紫铜、铝、黄铜、铁和碳钢(含碳0.5%)以及不同厚度的铝和黄铜进行测量，验证理论分析结果。结果表明,PAPE技术测量热扩散率较大、厚度较厚的材料更加精确、有效。

Influence of the length and the diffusivities of the samples on measured results and the applicability of the photoacoustic piezoelectric (PAPE) technique have been studied according to a simplified thermoelastic theory of the PAPE method. The PAPE technique based on a simplified thermoelastic theory was proposed. The relationship between the amplitude and phase of the PAPE signal and the frequency modulation were confirmed. Simulations were performed to investigate the measurement accuracy of the different materials with the same thickness and the identical materials with different thicknesses. For proving theoretic results the experimental system was developed to research for thermal diffusivities of red copper, aluminum, brass, iron and steel (C: 0.5%) whose thicknesses of is 2 mm. In addition, the thermal diffusivities of aluminum and brass with different thicknesses were also investigated by the experimental system. It shows that the PAPE technique can be employed for the accuracy measurement of the samples of the better heat conductivity properties and the thicker length.