从激光在厚试样中入射和受激发荧光在试样中出射时光能的吸收与散射损耗的基本原理获得了光学系统接收荧光的归一化光强表达式。给出了迭代法、ＦＦＴ方法的数学模型，进行了计算模拟，并分析比较了ＦＦＴ方法和迭代法的计算量和计算精度。给出了用ＦＦＴ法层析恢复后的图像 The normalized light intensity expression of the fluorescence received by the optical system is obtained from the basic principle of absorption and scattering loss of light energy when the laser light is incident on and excited by the thick sample. The mathematic models of iterative method and FFT method are given, and the calculation and simulation are carried out. The computational complexity and computational accuracy of FFT method and iterative method are analyzed and compared. The recovered image is given by FFT method