The present invention relates to a spirobenzylamine-phosphine, preparation method therefor and use thereof. The compound has a structure represented by formula (I), wherein n=0 to 3; R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 and R 9 having a value as defined in claim 1. Starting from the substituted 7-trifluoromesyloxy-7'-diarylphosphino-1, 1'-spiro-dihydroindene, the compound is synthesized in a two-step or three-step reactions. The new spirobenzylamine-phosphine is complexed with an iridium precursor and is subjected to ion exchange, to give an Iridium/spirobenzylamine-phosphine complex comprising various anions. The spiro benzyl amine-phosphine/Iridium complex according to the present invention may be used for catalyzing asymmetry hydrogenation of a variety of alpha-substituted acrylic acids, has high activity and enantio-selectivity, and has a good prospect of industrialization.