The invention discloses a risk assessment method for wide-range crop diseases. The method comprises the following steps that: selecting the n pieces of meteorological parameters of a monitoring area,giving an attack earlier stage meteorological early waning, carrying out meteorological encryption monitoring, calculating each meteorological parameter to obtain a disease occurrence posterior probability, predicting a meteorological multi-factor disease probability, adopting an inverse distance weighted method to carry out spatial interpolation, generating an accumulated meteorological risk map,generating a remote sensing growth vigor map, and generating a disease occurrence appropriateness map. The method has the characteristics that comprehensive information, including meteorology, crop habitats, representation after crops are stressed and the like, can be comprehensively considered for giving a disease early warning, and the method can be reused by various main crop diseases.