A model for laser scanning confocal microscopy with three media is given to calculate the point spread functions. (PSFs) According to Hammoum’s representations, we obtain the representations for three media. The effect of the dipole orientation on the PSFs is discussed. Several PSFs are compared. Then we analyze the effects of the pinhole on the PSFs, the energy collected and the signal to noise ratio. Calculations show that the detection PSF for the dipole averaged over all orientations is better than those for the dipoles along the x axis and the z axis. The total is smaller than the illumination PSF and the detection PSF. The total PSF after the pinhole diminishes as the pinhole decreases. The curves of the energy collected for the circular pinhole and the square pinhole are similar, but the signal to noise ratio for the circular pinhole is better than that for the square pinhole.