This invention relates to a method for imitating data flow cutoff, applying logical chip system with imitating data flow cutoff function. It comprises the following steps: A, the logical chip will transfer the data flow between data resource and rear circuit, deciding whether it reach to cutoff space, if it is, go to step B; if not, go on step A; B, knocking off the data flow, deciding whether it reach to the cutoff time according to the transmitted signal, if it is, return to step A; if not, go on step B; C, closing the test, blinding the cutoff function. Said invention can realize imitating data flow cutoff with various speed and interface on line, and control the type, time and space of the cutoff precisely.