Regional mobility of economic production factors accelerates the globalization of the associated economies and impacts firm diffusion trends. The Belt and Road Initiative aims to facilitate the orderly flow of economic production factors along the Sino-Europe Economic Corridor. However, little is known about the effects of locational accessibility on firm relocations with such an initiative. Conceptualizing locational accessibility based on elementary production factors, this paper proposed a methodological framework to analyze the potential firm diffusion trends by applying the percolation theory in a multimodal freight supernetwork. The empirical analysis concerns two typical manufacturing industries along the Sino-Europe Economic Corridor. The results show that the percolation transition happens during the diffusion of the two manufacturing industries considering land rent, labor cost, and freight transport cost as the elementary production factors. It is found that the improvement in transport accessibility accelerates the diffusion trends of the manufacturing industries, although the bottleneck regions for the diffusion of both industries do not change comparatively. The proposed methodological framework acts as an efficient testbed for analyzing the regional diffusion trends of different types of industries.