For the photon counting integral imaging system in a low-light environment, this paper proposes an element image enhancement algorithm based on the composite photon counting model and the Lucy-Richardson algorithm. First, in compliance with the integral imaging principle, 3DSMAX software is used to simulate the target element image collected by the synthetic aperture integral imaging system. After normalization of the target element image, the photon counting element image is obtained via the photon counting model. Then, it is processed in light of the composite photon counting model and its quality is enhanced in view of the additivity of the Poisson distribution. Finally, the Lucy-Richardson algorithm is iterated to enhance the element image and the reconstruction formula is employed to generate the reconstructed image. Experimental results show that the peak signal-to-noise ratio of the enhanced element image increases with the algorithm iteration number and gradually stabilizes. In addition, enhancing the element image delivers a better reconstruction result than the conventional maximum likelihood estimation method.