相关性规则是英美法的一项基础性证据规则。相关性规则适用于任何形式的证据资料，在适用范围上具有广泛性。判断一项证据是否具有相关性取决于两个方面，即证据针对的待证事实是否具有实质性，以及证据对于待证事实是否具有证明性。除非法律另有规定，具有关联性的证据一般都可以采为证据。但是，依据普通法传统，法官在某些情况下亦可排除某些具有关联性的证据。 Relevance rules are a basic rule of evidence in Anglo-American law. Relevance rules apply to any form of evidentiary material and are broad in scope. Determining whether a piece of evidence is relevant depends on two aspects, namely, whether the evidence is substantiated for the facts to be proved and whether the evidence is substantiated for the facts to be certified. Unless otherwise provided by law, evidence of relevance can generally be taken as evidence. However, based on the common law tradition, judges may also exclude certain evidence of relevance in certain circumstances.