The invention discloses an impact risk warning method on the basis of multi-parameter critical coal dust quantity indexes. The impact risk warning method includes drilling 2-3 groups of drilled holes in to-be-warned working regions, recording the weight of drilled coal dust in each meter of each hole, counting the weight of the coal dust with the particle diameter larger than 3mm in each meter of each hole and counting weight proportion of the coal dust with the particle diameter larger than 3mm in each meter of each hole; analyzing coal dust quantity values obtained by means of recording and computing, comparing the coal dust quantity values to critical coal dust quantity values, and predicting whether impact risk warning needs to be carried out on the regions or not according to four warning decisions including dynamic phenomenon records, general critical coal dust quantity analysis, segmented critical coal dust quantity analysis on the drilled holes and coal dust particle size analysis. The impact risk warning method has the advantage that impact risks can be accurately and reliably warned by the aid of the step-by-step warning method.