热力学图是科学家及工程师用来表示一物体（多半是流体）热力学状态及其变化的图。例如T-s图（温度熵图）就可以说明一流体在压缩机中的温度及熵的变化。

以下是一些常见的热力学图：

气象学特别会用到以下的热力学图：

Thermodynamic diagrams are diagrams used to represent the thermodynamic states of a material (typically fluid) and the consequences of manipulating this material. For instance, a temperature-entropy diagram (T-S diagram) may be used to demonstrate the behavior of a fluid as it is changed by a compressor.