The traditional detection methods for monitoring the biomass, protein, chlorophyll content and other key indicators in the growth of chlorella have some problems, including complicated operation, slow detection speed and difficult large-scale application. In this study, a fast and efficient monitoring method for the key indicators in the growth of chlorella was established using near infrared spectroscopy and chemometrics. Near-infrared spectroscopy was used to collect near-infrared spectra of chlorella algal fluid at different growth stages, and standard methods were used to detect the biomas...