This invention relates to a turbocharger multiple-series adjustable boost system, which belongs to combustion engine technique field. The system comprises diesel engine air inlet pipe, diesel engine, diesel engine discharge pipe, high-pressure turbine stage by-pass conduit and by-pass valve, high-pressure turbine stage by-pass conduit, high-pressure turbine stage, high and low pressure turbine connecting pipe flow change-over valve, high and low pressure turbine connecting pipe, low-pressure turbine stage by-pass conduit, low-pressure turbine, intercooler, high booster by-pass conduit and by-pass valve, high booster by-pass conduit, high blower, high and low pressure booster connecting pipe flow change-over valve, high and low pressure booster connecting pipe, low pressure booster by-pass conduit and low pressure booster, wherein the diesel engine is connected with diesel engine air inlet pipe and diesel engine discharge pipe separately, and the high pressure turbine outlet is connected with the low pressure turbine through the high and low pressure turbine conduit. By said invention, it can realize single-stage turbocharging, successive turbocharging and two-stage turbocharging.