In this paper an annular aperture method for laser speokle photography is proposed. The autocorrelation of an annular aperture function is oaloulated. The intensity distributions of the diffraction halos single exposure speokle patterns recorded by annular apertures with various internal to external diameter ratios η(,η = 0, 1/2, 8/4, 5/6, 7/ 8)are given, and these distributions are normalized by total diffraction intensity. It is shown that the intensity distribution of the diffraction halo is of rotational symmetry and the intensity at the border of tlie diffraction halo is increased remarkably,while the intensity at the intermediated region of the difFraotion halo may be on a fairly high lever when an annular aperture with, an appropriate ratio η is used. Therefore not only filtering in all directions at the border of the diffraction halo oan be carried out to achieve isothetios with high sensitivity along arbitrary direction，but also the widest variable sensitivity region can be obtained. An example to demonstrate this method is given. The experimental results agree very well with the theoretical analyses. It can be seen from the experimental results that 5/6 is the appropriate internal to external diameter ratio because consideration of high sensitivity, wide variable sensitivity region and short exposure time is given in this case.