Current range-gated imaging methods based on triangular or trapezoidal models face significant limitations in terms of the accuracy and precision of three-dimensional (3D) reconstruction. Here, we establish a range-gated 3D super-resolution image reconstruction method based on a Gaussian-range-intensity model. A denoised optimization method for image preprocessing is established to improve the distance accuracy of the reconstruction. The experimental results show that the model can reduce the error of target distance by 64% and possess the reconstruction of multiple kinds of targets with a distance resolution of 1.5 cm and lower noise, realizing better reconstruction results compared with the existing range-gated 3D imaging techniques.