Raman tweezers, a novel technique that combines Raman spectroscopy with optical tweezers, has the potential to become an effective tool for analysis single cell suspended in solution. To real-time investigate the biochemical proceedings in single cell, a Raman tweezers setup was used to trap a single instant active dry yeast cell and to acquire the real-time Raman spectrum of the trapping cell from dormancy to activation cultured in 2.0% (W/V) glucose. During the activating process, the intensity of bands derived from protein or lipids, such as 1000 cm^-1，1445 cm^-1，1655 cm^-1, were not changed evidently. The intensity of the 1603 cm^-1 band, which was considered as the signature of metabolic activity, was not changed evidently too. But the bands at 531cm^-1，652cm^-1，1053cm^-1，1364 cm^-1, which were assigned to trehalose, or glucose-base carbohydrates, were increased as the cell grew. This phenomenon, occurred in seven individual experiments of ten repeats using a batch of instant active yeast cells as tested cells, but did not occur when other batches of instant active yeast cells were tested. This peculiar process of adaptation was recorded by real-time Raman spectrum and the result indicates Raman tweezers is an effective tool for single-cell analysis.