A numerical simulation of electron cyclotron current drive in HL-2A tokamak is performed with the relativistic Fokker-Planck equation incorporated into a ray tracing code. With the single-null divertor configuration on the HL-2A tokamak, the current drive for the ordinary electron cyclotron wave, injected from the low field side, are analyzed. Numerical results show that current drive efficiency is low and can be affected d...