This paper investigates which annotation scheme of dependency treebank is more congruent for the measurement of syntactic complexity and cognitive constraint of language materials. Two representatives of semantic-and syntactic-oriented annotation schemes, the Universal Dependencies (UD) and the Surface-Syntactic Universal Dependencies (SUD), are under discussion. The results show that, on the one hand, natural languages based on both annotation schemes follow the universal linguistic law of Dependency Distance Minimization (DDM); on the other hand, according to the metric of Mean Dependency Distances (MDDs), the SUD annotation scheme that accords with traditional dependency syntaxes are more expedient to measure syntactic difficulty and cognitive demand.