A Comparative Study on the Rules of Criminal Evidentiary Admissibility of Cross-Strait Mobile Communication Data

In the era of the digital economy, mobile communication data has become crucial evidence in criminal prosecutions. Due to differences in legal traditions and governance logics, the Chinese mainland and Taiwan Region of China have developed distinct systems of digital evidence admissibility rules. Through a comparative study, this paper finds that the Chinese mainland adopts a “normative construction” model driven by statutory law, with the “three attributes” (authenticity, legality, relevance) and “integrity” at its core, ensuring the authenticity of evidence through ex ante rules. In contrast, Taiwan Region of China relies on leading judicial judgments for “case-by-case development,” forming a preponderant evidence standard centered on the “authentication procedure,” which highlights the flexibility of ex post review. Such differences are specifically reflected in the preferences for carriers and procedures of original evidence, the stringency versus flexibility regarding duplicates, and the tendency to exclude versus admit substitutes. The study argues that both models have their respective advantages and disadvantages in terms of certainty and adaptability, which are influenced by the inquisitorial and adversarial litigation cultures behind them. This paper aims to provide intellectual reference for the mutual learning and future development of evidence rules across the Strait.