Abstract: In order to observe the pathological changes in liver and spleen of chickens with Escherichia coli infection, clinical samples of diseased chickens were collected from poultry farm in Kunming region of Yunnan Province and were used for isolation and identification of pathogenic bacteria. The presence of Escherichia coli evidenced the colibacillosis of the chickens. The liver and spleen of chickens were collected to prepare paraffin sections, and the pathological changes were observed using light microscope. The main pathological changes of the liver tissues involved in edema and coagulation necrosis, and the glassy degeneration in the area with serious lesions was observed. The main pathological changes of spleen tissues included extension of tissue space, sparsity and shrinkage of spleen lymphocytes, hyperplasia of stromal cells, presence of rod-shaped cells, and increased number of phagocytes.