Abstract: In view of problem of fracture of cylinder in strength test and type test for column cylinder, the paper put forward a scheme of crack monitoring of column cylinder based on acoustic emission technology. The scheme uses acoustic emission technology to capture, analyze, process and display elastic wave of crack produced in compression process of column, uses time difference location method to get position of acoustic emission source, and uses wavelet packet technology to process acoustic emission signal to improve location precision. The test result showed that it is feasible to use acoustic emission technology to produce and development and make risk analysis of crack and weld of column cylinder.