The invention relates to a preparation method for 1-methyl-1-(beta-hydroxy ethyl) guanidine sulfate (creatinol sulphate), belonging to the preparation method for guanidine derivatives. The preparation method for creatinol sulphate comprises the following steps: (1) cyanamide aqueous solution, methyl alcohole and concentrated sulfuric acid reacting in the temperature of 10 DEG C to 40 DEG C for 30min to 90 min; (2) dropwise adding N-methyl amino-alcohol into the solution in the step (1), reacting for 3h-5h in the temperature of 30-80 DEG C, decompressing and concentrating; (3) adding organic solvent into the concentrated solution, separating out creatinol sulphate and crystallizing, and obtaining creatinol sulphate finished product after washing and drying. The preparation method has mildreactive conditions, is simple and convenient to operate and practical, has low toxicity owing to taking water as solvent, low cost and low vitality, simultaneously is simple and practical in the post treatment, and saves time and energy. The obtained product has high yield and good purity; and the purity of the product can reach 93%-99%.