The problem of lossless compression of bi-level speckle images is studied with the statistical properties of dynamic speckle. A bi-level speckle image distortion coder is designed, which consists of image cutting, displacement estimation, prediction, context formation and entropy coding. The main features include the fast algorithm of speckle displacement estimation, the optimized prediction based on the statistical characteristics of speckle, and the adaptive arithmetic coding. The working process and principle of the coder are introduced. The experimental results show that the compression performance of the bi-level speckle image distortion-free encoder is greatly improved.