Non-line-of-sight (NLOS) imaging relies on capturing light that has been weakened due to multiple reflections and recovering the occluded scene with high quality is very challenging. To improve the quality of NLOS imaging, an active mode single-pixel NLOS imaging reconstruction framework based on the second-order correlation function and diffraction inverse operation is proposed. Under the collective effect of illumination pattern and single-pixel detector light intensity, the inverse imaging problem is first solved by a statistically weighted average, and then, an additional process is connected to reduce the influence of diffraction on reconstructed image quality based on the Fourier transform and inverse diffraction operation. The simulation and experimental results show that the proposed method with the Hadamard pattern and diffraction inverse operation, which achieved the SSIM value of 0.9286, is superior to the random pattern at a full sampling rate. The lens aperture size, pattern location, and the number of measurements have a significant effect on the system. Therefore, the proposed scheme has potential practical applications.