Abstract: Reflow-soldering is a sophisticated welding method on the electronic components.For precisely controlling the reflow-soldering,the control system adopts PIC18F6585 as the control core and the closed-loop feedback through thermocouple as to control the welding temperature.The language of the control system is written with C language and assembly language.Through the waveform control of different stage and the digital PI algorithm regulation,the power supply achieves precise control of the welding process.Experimental results validate that the control system of the power supply can accurately control the welding pressure,time and temperature,and has obvious advantages in the surface mount technology field.