Many Chinese compound characters consist of one semantic radical and one phonetic radical. The semantic radical is related with the meaning of the whole character. Characters sharing the same semantic radical constitute the semantic radical family. The difference induced by the size of the orthography family is neighborhood effect. The degree of semantic concentration of all Chinese characters formed by the same semantic radical is category consistency. Previous studies explored the semantic activation, neighborhood effect and category consistency effect of semantic radical under whole character priming paradigm. The limitations of previous studies include:(1) The whole character priming paradigm cannot separate the influence of the whole character.(2) Previous studies cannot compare lexical decision and semantic judgment directly, since the result of semantic judgments leads to the separation of "yes/no".(3) Previous studies examined the semantic activation, neighborhood effect and category consistency effect of the semantic radicals, but due to the limitations of the paradigm, they cannot integrate these influence factors. The present study intends to use the radical priming paradigm to investigate the effect of family size and category consistency on the semantic activation of semantic radicals in tasks of different processing depth.In experiment 1, we use the 2(Character type: transparent and opaque) × 2(priming condition: radical priming and **** priming) multi-factorial experiment design to validate the radical priming paradigm. The results showed that there was no significant difference in the reaction time of the two categories of Chinese characters under the **** priming condition. However, the reaction time of the semantic transparent Chinese characters was significantly shorter than that of the semantic opaque Chinese characters under the radical priming condition. The results indicate that the semantic radical’s meaning can be activated effectively. The radical priming paradigm is valid. In experiment 2 and experiment 3, the effects of family size and category consistency on the semantic activation of the semantic radicals are investigated in tasks of different processing depth. Experiment 2 used lexical decision task of a 2(character type: transparent and opaque) × 2(family size: large and small) × 2(category consistency: consistent and inconsistent) design. Experiment 3 used the semantic relevance judgment task of a 2(character type: S– —S– and S– —S+) × 2(family size: large and small) × 2(category consistency: consistent and inconsistent)design. Experiment 2 found the family size effect on the semantic activation of the semantic radicals. The meaning of semantic radicals of small families is easier to activate than that of semanticradicals of large families. Experiment 3 found the category consistency effect on semantic activation of semantic radicals. The meaning of semantic radicals of consistent category is easier to activate than that of semantic radicals of inconsistent category. Moreover, category consistency effect on semantic activation of radicals is regulated by family size in error rate. The whole study shows that the family size and category consistency can affect the semantic activation of semantic radicals, and the depth of processing will affect the different behaviors of the two factors. In the shallow processing task, we only found the family size effect on the semantic activation of the semantic radicals. While, in the deep processing task, we only found the family consistency effect on the semantic activation of the semantic radicals, and this effect is regulated to a certain extent by the family size of the semantic radicals. Moreover, we also found that the category consistency will affect the direction of family size effect of the semantic radicals.