Based on the binary phase-field model, the phase-field model coupling with solute field，temperature field and flow field was developed. The mass and momentum conservation equations are solved by using the Simple algorithm, and the thermal governing equation is numerically solved using an alternating implicit finite difference method. The dendrite growth processes during isothermal and non-isothermal solidification of the binary alloy under convection was simulated. The difference in dendrite growth, solute distribute and temperature distribution were investigated. The result of dendrite growth during isothermal and non-isothermal solidification were compared.The effect of latent heat on the dendrite growth under convection was analyzed.