Objective To address the limitations of traditional single-point moisture measurement in complex drying environments, a multi-conductor array capacitor device was designed for moisture content measurement inside a grain dryer.Methods An array of 8 conductor rods was arranged to measure the capacitance between each pair of adjacent rods, from which the average dielectric constant in the inter-rod regions was calculated to enable real-time moisture monitoring during the grain drying process.Results High-precision capacitance measurements were achieved using an FDC2214 capacitive sensor controlled by a Raspberry Pi Pico W. The relationship between the dielectric constant in regions with varying moisture content and the corresponding water weight was validated, generating a two-dimensional dielectric constant distribution map. In environments with uneven humidity distribution, the device rapidly and stably detected moisture diffusion and accurately fitted the improved Dobson model. During the fitting process, the maximum standard deviation of the dielectric constant was 3.98, with an average value of 1.27.Conclusion By adjusting the physical structure of the test setup, the device can measure the average moisture distribution in any spatial unit of grain.