The invention relates to crystal form VII of methylsulfonic acid dabigatran etexilate and a preparation method thereof. The crystal form VII is defined by an X-ray powder diffraction pattern at a characteristic peak of diffraction angles 2 theta and DSC. The preparation of the crystal form is microwave assisted crystallization by adding a solid form of the methylsulfonic acid dabigatran etexilateto anhydrous ethanol, disposing into a suspension with the concentration of 0.05 to 0.13 g solute/g solvent, under the conditions of 15 to 25 DEG C constant temperature suspension and stirring, conducting microwave treatment for 5 to 10min, turning off a microwave generating device, and continuing to conduct constant temperature suspension under 15 to 25 DEG C for 8 to 24h; extracting and filtering suspension liquid, and drying a methylsulfonic acid dabigatran etexilate crystal product to constant weight. The preparation method of the novel crystal form of the methylsulfonic acid dabigatran etexilate has the advantages of low solvent toxicity, small environmental pollution, simple process, short time-consuming, large particle size of prepared products, easy filtration, high solubility, high purity, good thermodynamic stability and the like.