In order to determine the equation of state in the sospin asymmetrical nuclear matter，we have been engaged in find an experimental observable which sensitively shows the information of the nucleon-nucleon cross section and the symmetry potential in the intermediate energy heavy ion collision by using the isospin dependent quantum molecular dynamics in recent years. As a result, we have found several sensitive probes for extracting the information of the in-medium nucleon-nucleon cross section and the symmetry potential in the equation of state of the isospin asymmetrical nuclear matter. The mechanism of the above probes are investigated in detail. A brief summary and comments on the above results and the prospect of finding more probes in the future are presented.