In this paper, we present a method for interpreting Chinese declarative sentences by Head-driven Phrase Structure Crammer (HPSG), a unification-based grammatical formalism with situation semantics as its semantic theory. The primary reason for using this approach is that HPSG performs syntactic and semantic analysis in an integrated way and situation semantics provides a realistic and sound theoretic foundation. Two kinds of feature structures, basic and complex, are used in the semantic representation of words, phrases and sentences. The basic types are quantifier, indexed-object, circumstance, and description types. They are used to represent the meanings of lexical signs and unquantified phrasal signs. The complex types are quantifiedobject types and quantified-circumstance types. Complex types are for representing quantified phrasal signs. The process of semantic interpretation is carried out by combining the semantic representations of heads and complements/adjuncts according to their types and by generating a new semantic representation for the larger phrase. A practical system is described with a set of examples.