We present a method, intensity fluctuation modulation (IFM), to obtain a full-field laser speckle microvessel image. Different from laser speckle contrast analysis, IFM imaging is insensitive to flow velocity and can be used to reconstruct microvessel images with higher spatial resolution and SNR. An in vivo animal experiment on a mouse pinna is conducted to demonstrate that IFM imaging is capable of achieving laser speckle microangiography.