Insulator icing directly threatens the safe and stable operation of overhead lines, and through space electric field monitoring, non-contact insulator icing status recognition and ice flash warning are expected to be realized. For this reason, the spatial electric field distribution characteristics of 110 kV composite insulators are simulated, the effects of different icing patterns and their discharge levels on the spatial electric field of the insulators are analyzed, and a non-contact icing monitoring method for composite insulators based on the spatial electric field is discussed. Research results show that in three cases of rime, glaze, discharge, the spatial electric field of the composite insulator along with the string distribution are of obvious differences. When the degree of icing increases and electric discharge develops, the insulator spatial electric field amplitude increases. Spatial electric fiels signals are monitored at the cross-arm with d=0.3 m, and directly opposite to the last three pieces of the 110 kV composite insulator, which verifies that it is feasible to identify icing degree and arc development. The results of the study can be used as a reference for overhead line insulator icing monitoring and ice flash early warning.