Abstract: The fragmentation of Nocardia was investigated by ultrasonic method and cell autolysis, and both could fragment well the microbe. But, the latter requires longer time than the former. The total time required and power output are the key influencing factors of ultrasonic method, and frequent short-time fragmenting steps and 1.5 g/L bacterium density are beneficial to cell fragmentation. In the cell autolysis process, time is the key factor, and that the NaCl density is 1% and temperature at 50°C is beneficial to cell autolysis in which the collaborative effect of all enzymes in Nocardia is better when pH value is 7-9. The result of IR spectral analysis indicated that the categories of radicals found in cell walls after either ultrasonic method or cell autolysis are almost the same.