The invention relates to the field of livestock feed, and discloses a fermented feed containing rapeseed meal, and a preparation method of the fermented feed. The preparation method comprises the steps of carrying out solid state fermentation on fermentation raw materials including the rapeseed meal, compound microbial strain, sodium hydroxide and water, and then drying to obtain the fermented feed containing the rapeseed meal. According to the preparation method, lactobacillus plantarum, bacillus subtilis, bacillus licheniformis and saccharomyces cerevisiae are taken as microbial strains for the solid state fermentation of the rapeseed meal, and the aim of remarkably improving the contents of protein and small peptide of the rapeseed meal can be realized in the environment of solid state fermentation in virtue of metabolic activity and interaction of all microorganisms, so that the application of the rapeseed meal in the feed can be further expanded.