The Competent Cell Preparation and Transformation Kit for Saccharomyces Cerevisiae produced by Solarbio enables fast, convenient, and efficient preparation of highly active Saccharomyces cerevisiae competent cells and plasmid transformation. This kit provides almost all the reagents needed except for the culture medium, no dilution and preparation are required, the operation is simple and fast, and the competent cells can be prepared within 30 minutes after the yeast is cultured, which can be used for yeast hybridization experiments and yeast library construction experiments. For Saccharomyces cerevisiae transformation, yeast cells are cultured using the buffer solution provided in the kit to be transformed, then competent cells are mixed with plasmid DNA and Carrier DNA to be transformed, and incubated with transformation solution. Carrier DNA is short, linear, single-stranded DNA that promotes the entry of plasmids into yeast cells during the uptake of exogenous plasmid DNA by yeast cells, and also protects plasmids from degradation by DNases.