A two-dimensional MHD simulation model is presented to study stochastic reconnection at the magnetopause. The simulation indicates that in an open system with strong velocity shear and large Reynolds and magnetic Reynolds number (R and Rm), stochastic reconnection can take place in the magnetopause current sheet when the interplanetary magnetic field has a southward component, leading to the appearance of irregular mesoscale and small-scale structures (IMSSSs). The larger the R and Rm are, the more IMSSSs are produced. The stronger the flow shear intensity is, the faster IMSSSs occur. Mesoscale and small-scale structures can coalesce to form large-scale ones if R and Rm are midranged (10 to 200), while large and mesoscale structures can break into smaller ones if R and Rm increase. It is expected that stochastic reconnection plays an important role in the solar wind-magnetosphere coupling. ¿ American Geophysical Union 1995