The Functional Resonance Analysis Method (FRAM) is extensively used to qualitatively analyze the risk of socio-technical systems. To quantitatively assess system risk, previous studies have explored various approaches to integrate FRAM with Bayesian Networks (BN). However, the process of mapping FRAM to BN relies heavily on subjective judgments, often lacking traceability and repeatability. In this paper, a standardized method for mapping FRAM to BN is proposed through introducing Accimap. Firstly, each FRAM’s functional hexagon is transformed into an Accimap, with the six aspects of functions corresponding to Accimap factors. In addition, their internal coupling relationships are obtained by cause and effect investigation in Accimap. Secondly, multiple Accimaps are connected based on the upstream-downstream couplings between functions in FRAM. Through this method, (i) the aspects of FRAM are transformed into Accimap factors and then BN nodes, and (ii) the couplings among the six aspects of functions and across multiple hexagons are converted into BN directed edges.