This paper presents a myocardial ion channel simulation platform, a system for simulating the electrophysiological activities of myocyte. The action potential of cells from each part is different due to their electrophysiological properties, so that the system doesn't regard the myocyte as a whole. It contains punkinje fiber cells, endocardial cells, midmyocardial cells and epicardial cells. The system could display the cellular electrophysiological activities under the effect of drugs and could compare with the activities under the condition without drugs. The simulation results can be quantified precisely. The platform is realized in MATLAB and has passed the test.