Abstract: The truth conception one holds is crucial to the basic standard for finding out fact. In adversarial criminal justice, the objective truth and the legal truth are representative doctrines in the historical evolution of theories of evidentiary truth. Given the rise of negotiated criminal justice in China, the corresponding transformation of the truth conception is necessary to render the procedural operation more internally coherent. Contractual truth, as a procedurally functional truth conception, is constructed through agreements between the prosecution and the defense. It emphasizes the subjectivity of procedural participants, which aligns with the normative ideal of negotiated justice, namely, resolving conflicts through peaceful and consultative means. The three-dimensional path to contractual truth comprises pre-trial and trial-stage mechanisms. Firstly, pre-trial procedures ensure clarity and validity by specifying the contents of plea statements and recognizing the defense counsel status of duty lawyers. Secondly, trial proceedings safeguard truth and legality by verifying the factual basis, voluntary intent, and adherence to due process.