Abstract: Disastrous space weather events include solar flares, solar proton events, magnetic storms, high-energy electron storms and ionospheric storms, etc. Accurate forecasting and early alert information help to take timely measures to avoid or reduce losses. At present, the overall level of space weather forecasting is not high enough, and there are significant differences in the maturity of forecasting and alert services for different space weather events in China. The standardization of space weather early alert service needs to be improved. Based on the analysis of the characteristics and impacts of space weather events in addition to existing services and related researches, alert scales of disastrous space weather events were discussed in this paper. Suggestions were proposed as follows: identifying space weather events based on the synthesis of multiple environmental factors; establishing ionospheric storm indexes covering both internal and external disturbance sources; setting up specifications based on the suitability analysis of autonomous detection data to adapt to current monitoring capabilities and real-time space weather services; refining the classification of professional users to design tailored products for guarantee.