The highly sensitive laser absorption spectroscopy technology is applied to the field of microbial growth measurement to realize the real-time monitoring of the microbial growth process and the drawing of growth curves taking Escherichia coli as an example. A set of experimental measurement equipment is designed and built to monitor and fit the second harmonic signal of carbon dioxide (CO2) generated by metabolism of Escherichia coli in real time. The growth curves of E. coli are measured at 25, 26, 29, 32, 34, 37 and 43 °C. The experimental results show that the measured growth curve can accurately reflect the adjustment period, logarithmic phase, stable period and decay period of E. coli growth at different temperatures, which proves that the microbial growth metabolite (CO2) method based on laser absorption spectroscopy technology can be well applied to the field of microbial growth measurement.