The invention discloses battery slurry of a lithium ion battery, a preparation method thereof, an electrode and the battery. The battery slurry contains an N-methyl-2-pyrrolidone and carbonate ester mixed solvent. The preparation method of the battery slurry includes the following steps that firstly, active materials and conductive agents are stirred and mixed; S2, N-methyl-2-pyrrolidone and carbonate ester are stirred and evenly mixed in a closed container and baked, and the N-methyl-2-pyrrolidone and carbonate ester mixed solvent is obtained; the N-methyl-2-pyrrolidone and carbonate ester mixed solvent obtained in the second step is added into products obtained in the first step and stirred and evenly mixed; an adhesion agent and water are added into products obtained in the third step and are stirred and evenly mixed. The N-methyl-2-pyrrolidone and carbonate ester mixed solvent can improve the adhesion performance of pole pieces, the adhesion capacity between the pole pieces and a base material can also be improved, it is prevented that power falls from the pole pieces and the pole pieces fall off, the adding quantity of the adhesion agent is reduced, the adhesion performance of the pole pieces can be guaranteed, after liquid injection, carbonate ester can be dissolved in electrolyte, and performance of a battery cell is not affected.