The invention discloses a chemical exchange saturation transfer (CEST) imaging method and device based on a variable acceleration sensitivity encoding method, and belongs to the field of magnetic resonance imaging. In the method, Fourier transform is carried out on K-space data formed by a measured object in CEST imaging to obtain image space folding data of each voxel, wherein the image space folding data includes at least one undersampled frame accurate image with the acceleration factor R1 being greater than or equal to 1 and a plurality of other to-be-reconstructed undersampled frame images with the acceleration factor being not less than R1; and then image reconstruction is carried out on the to-be-reconstructed undersampled frame images with the acceleration factor being R2. The sensitivity map of the traditional SENSE method can be modified by using undersampled frames. The reconstruction error of the method is basically the same as that of the traditional SNESE method which applies a low acceleration factor in a CEST source image, but the speed of the method is twice or more the speed of the traditional SENSE method. Since it is unnecessary to adopt fully sampled frames, the method is particularly applicable to three-dimensional (3D) CEST imaging.