Abstract: Considerable progress has been made since 1990 in the research of the critical conditions of river blocking by debris flows, including the dynamic simulation test, correlation analysis, theoretical mechanical analysis of momentum and kinetic energy leading to the presentation of various discriminant formulas for critical conditions. The author in this study contends that some aspects remain resolved concerning mechanical mechanism, numerical modeling, prototype simulation test and multiphase remote sensing application to the research of river blocking by debris flows. The techniques such as remote sensing and geographical information system, prototype simulation test and discriminant formulas should also be applied in the future research aiming at providing scientific base for the disaster prevention and reduction.