A multi-channel constant voltage and constant current converting controller is provided. It comprises a multi-channel balance circuit and an error amplifier circuit. The multi-channel balance circuit receives a first voltage signal and load current detecting signals and outputs a second voltage signal and amplifying load current detecting signals. The error amplifier circuit receives the second voltage signal, the amplifying load current detecting signals and a reference voltage and outputs an error amplifying signal. The error amplifier circuit outs the error amplifying signal according to the reference voltage and the maximum value between the second voltage signal and amplifying load current detecting signals.