In the present paper, I classify the modality meanings of each auxiliary verb used in modern Chinese and examine the negative forms as well as the relationship between the negative forms and modality meanings. First of all, I categorize 10 auxiliary verbs (yao, neng, hui, keyi, xiang, yinggai, keneng, dei, gan, yuanyi) based on the level of usage and examine their modality meanings and negative forms. There are characteristics dependent on the level of usage. As such, higher level of usage entails diversity in modality meanings whereas lower level of usage is followed by limited range of modality meanings. Next, I examine the relationship between the modality meanings and negative forms. The auxiliary verbs with dynamic modality and the auxiliary verbs which indicate “probability” of epistemic modality have symmetric negative forms. On the contrary, the auxiliary verbs which indicate “possibility” and “necessity” of epistemic modality have asymmetric negative forms. Lastly, I examine the auxiliary verbs with asymmetric negative forms. I find that these asymmetric negative forms also have certain regularity within the overall system of auxiliary verbs.