The new generation of detection equipment puts forward an urgent need for high sensitivity detectors. Looking at the development status of semiconductor detection devices, the sensitivity and channel size of traditional silicon-based detectors cannot meet the needs of the future. Diamondene has excellent performance such as high carrier mobility and wide band gap. Its excellent electronic characteristics are expected to effectively improve the sensitivity performance of the detector and provide a new way for the development of the next generation of detectors. However, the detection mechanism based on diamondene is still unclear. Based on the above problems, the analytical model and mechanism of the transistor channel are first studied. By analyzing the relationship between the surface potential distribution of the current channel and the effective channel size in the working state and the sensitive characteristics of the two-dimensional material electrons of the channel, a theoretical model of the transistor detector based on the electronic characteristics of the channel material is constructed, and the working characteristics of the detector are revealed. Based on the finite element simulation, the working mechanism, potential and electron distribution of the transistor detector are simulated. The simulation results show that the mobility level of the diamondene-based detector is 2.5 times that of the traditional silicon-based detector, which theoretically verifies the hypersensitivity detection characteristics of the diamondene-based detector. The research work in this paper is of great significance to the design and application of a new generation of carbon-based ultra-sensitive detection devices.