Thermal rectifiers, which actively control heat flow direction analogous to electronic diodes, hold great promise for next-generation thermal management technologies. Two-dimensional (2D) materials have attracted interest due to their compatibility with modern electronics (e.g., electrical properties and structural flexibility). Most characterization experiments employ the H-type method with suspended electrodes as heaters and resistance thermometers to measure the thermal rectification ratio (TR), yielding only spatially averaged values and obscuring local heat transport. Resolving the temperature distribution is essential for understanding the underlying mechanisms. Although thermoreflectance imaging directly measures temperature distributions, its application to suspended transparent 2D samples suffers from signal coupling between the transparent 2D material and the underlying substrate. To address this, this work proposes an adapted thermoreflectance imaging method specifically designed for temperature mapping of suspended transparent 2D materials. The key innovation lies in decoupling the mixed reflectance signals of the sample from substrate by independently controlling sample’s temperature rises via electrode heating. Specifically, uniform heating of the sample using both electrodes provides a reference calibration signal. The ratio of this reference signal to the signal acquired under desired heat flow conditions enables reconstruction of the intrinsic temperature distribution of the suspended 2D sample. Using this method, the 2D temperature distributions of a triangular single-layer WSe₂ on PMMA hybrid sample are measured under both forward and backward heat flow conditions. The obtained TR of the WSe₂/PMMA sample is 8.90%, whereas a control sample consisting of only PMMA exhibits a TR of only about 0.59% under the same geometrical asymmetry. Comparative analysis reveals that the observed thermal rectification effect primarily arises from the synergistic action of shape asymmetry and the temperature-dependent thermal conductivity of WSe₂. The geometrical asymmetry provides the structural basis, while the decrease of WSe₂ thermal conductivity with increasing temperature further amplifies the difference in effective thermal conductivity between the forward and backward heat flow directions. This adapted thermoreflectance imaging method offers an effective experimental tool for investigating heat transport mechanisms in suspended transparent 2D materials and lays a methodological foundation for optimizing thermal rectifier devices.