The invention disclosure an application of sinomenine in the preparation of a medicament for preventing and treating myocardial hypertrophy or a disease based on the myocardial hypertrophy. According to the invention, myocardium of a little mouse is stimulated and induced by means of a beta-receptor stimulant, isoprenaline, and a myocardial hypertrophy model for the little mouse is duplicated; the myocardial hypertrophy of a big rat is induced by means of abdominal aortic coarctation, and a myocardial hypertrophy model for the big rat is duplicated; Chinese herbal medicine monomer, sinomenine, of different doses is applied to the myocardial hypertrophy model for the little mouse and the myocardial hypertrophy model for the big rat respectively. After experimental studies on entire animals in terms of pharmacodynamics, a positive treatment effect is achieved, and a foundation is provided for the screening of new drugs.