When an image digital holographic microscopy (DHM) layout is employed, the Fresnel integral cannot be used in separating the reconstructed image from its conjugate image and background. However, combining image plane DHM with the phase-shifting in-line technique, the complex amplitude of reconstructed image can be obtained without using Fresnel integral, moreover the approximate error of reconstruction calculation is easily eliminated and the signal-to-noise ratio of reconstructed image is significantly improved. Since a normal incidence plane wave is used as the reference wave, the difficulty and complexity of phase aberration and phase unwrapping of DHM are remarkably decreased.