A control method for ice load running safety of blades of a wind generating set on the basis of blade mode detection comprises the following steps: (a) triggering a blade ice load running safety control system to be started and stopped according to a meteorological environment judgment signal; (b) determining a blade ice load running risk grade according to the total weight of a wind wheel coated with ice and the rotation 1P vibration acceleration amplitude of the wind wheel; and (c) outputting a unit power control signal according to the blade ice load running risk, selecting a preset power limiting value corresponding to the blade ice load running risk grade, and stopping running of the unit when the blade ice load running risk grade is dangerous. The invention further provides a control system for ice load running safety of the blades of the wind generating set on the basis of blade mode detection. Serious accidents such as blade cracking, breaking and collapse of the unit due to blade ice load running are avoided, running safety and running reliability of the unit are guaranteed effectively, and the generating capacity is improved.