Acid fracturing is one of the commonly used measures to increase production in carbonate reservoirs. The degree of inhomogeneous etch on fracture morphology plays an important role in the conductivity and final effect of increasing production after acid fracturing. With the aim to describe the degree of inhomogeneous etch more comprehensively，the inhomogeneous etch coefficient was introduced to characterize the degree of inhomogeneous etch. Firstly，the point cloud data of core slices before and after acid rock reaction was obtained by three-dimensional laser scanner，and through the software Geomgaic and Matlab the point cloud data was processed and the surface morphology characteristic parameters was calculated furtherly，including the extended interface coefficient in the horizontal direction and the standard deviation coefficient of acid corrosion height in the vertical direction，and the inhomogeneous etch coefficient was obtained by weighted summation. The higher the degree of inhomogeneous etch，the greater the coefficient of inhomogeneous etch. Considering the influence of different factors，the factors was sorted by parameter sensitivity analysis，and the order relationship of primary and secondary influencing factors was obtained as follows： acid concentration（59.94%）＞dolomite content（19.78%）＞rotating speed（14.08%）＞temperature（6.19%）. The proposal of inhomogeneous etch coefficient can provide a possibility for fine quantitative characterization of inhomogeneous etch degree of acid etched cracks，and also point out the optimization direction for acid fracturing design.