This paper discusses the syntactic derivation of the Spanish clitic cluster formation in which an accusative clitic of an embedded infinite verb that the matrix verb selects and a dative clitic of the matrix verb co-occur. The Person-Case Constraint, a universal constraint that only third person accusative clitic can co-occur with dative clitic in clitic double object construction, cannot satisfactorilly explain the phenomenon captured in clitic sequences constructed by movement of a clitic which refers to an argument of infinite verb. For the syntactic analysis of clitic cluster formation, I propose that a [+affix] feature of a dative clitic functions as a probe that attracts a goal(i.e., accusative clitic) with the same feature following Cluster Hypothesis proposed by Sabel(2001). Furthermore, I assume that person restrictions applied to clitic clusters are determined by animacy features of clitics. I argue that the syntactic properties captured between two different types of clitic clusters are due to whether the third person accusative clitic has shared [animate] feature with a functional head v before a clitic cluster is formed.