Within the framework of Systemic Functional Linguistics, this paper explores the functions and realizations of nonfinite clauses in English and Chinese. From the perspective of metafunctions, nonfinite clauses in English and Chinese are similar. From the angle of experiential metafunction, they do not have their processes directly located. Meanwhile, the degrees of their subject-participant’s participation are in a continuum with the stronger degree and the weaker degree as two poles. From the angle of logical metafunction, the embedding power of nonfinite clauses in English and Chinese are in a continuum with the stronger power and the weaker power as two poles; while nonfinite clauses in English and Chinese can also form the projection and expansion relations. From the angle of interpersonal metafunction, nonfinite clauses in English and Chinese have no mood choices, which means that they have no speech functions. Form the textual perspective, nonfinite clauses in English and Chinese can make the text coherent on account of the deletion of some information. From the perspective of realizations, the logical, interpersonal and textual metafunctions of nonfinite clauses in English and Chinese are realized through the similar covert ways, while the experiential metafunctions such as the location of process and participants serving as the Subject element are realized through a more grammatical means in English than in Chinese.