Physical equations of laser ablative hydrodynamic instability in the code EUL2D is given. Slide grids and some techniques in the calculation is reported. Simulation results of the EUL2D code are good agreements with those of the Takabe formula, the FAST2D code and the LASNEX code. Our numerical simulation reproduced the experimental result of laser ablative Rayleigh-Taylor instability in Osaka University. It is discovered that lateral ablation of electron conduction plays an important role in nonlinear evolution of the Rayleigh-Taylor instability with a longer wavelength ．