The invention belongs to the technical field of metering pump systems, and particularly relates to a metering pump system and a pressure adjust method. The metering pump system comprises an oil tank,an electronic control pressure adjusting valve, a safety valve, a filter, a cooler and a pressure relay. The metering pump system is characterized in that the oil tank communicates with the safety valve and a plurality of pumps, the safety valve and the pumps communicate with the filter through a pipeline, the filter communicates with the cooler, the cooler communicates with an output pipeline, the electronic control pressure adjusting valve is arranged at the communication position of the pipeline and an overflow pipeline, the overflow pipeline communicates with the oil tank, the output pipeline is provided with the pressure relay, and the pressure relay is connected with the electronic control pressure adjusting valve through a line. The metering pump system has the beneficial effects that sudden increasing of pressure of the local pipeline is avoided, by means of the technical scheme, the pressure of the system is increased stably, and defects in the prior art are overcome.