The colorimetric tube rack is made of acid and alkali resistant PP integrated injection molding, which can stably insert 12 10mm optical path colorimetric tubes at a 45 ° angle, making it easy to vertically observe the liquid level and scale; The base is embedded with a white reflective plate to reduce background color difference and improve visual color accuracy. The side ruler can directly read and cancel the liquid level, and the bottom can be disassembled to prevent liquid overflow. The whole machine is only palm sized and can be sterilized under high pressure, suitable for rapid colorimetric experiments such as COD, residual chlorine, phosphate, etc. in the classroom.