The invention discloses an automated instrument applied to nucleic acid extraction and continuous operation process of a mass spectrum sample application chip in biomass spectrometry analysis of a nucleic acid sample. The automated instrument comprises three main devices, namely, a nucleic acid extraction and purification device, a nucleic acid liquor relief distributing device and a mass spectrum chip sample application device, wherein nucleic acid in body fluid is extracted by using a magnetic bead method, a mechanical arm is utilized to complete a nucleic acid extraction action, the extracted nucleic acid is dispensed onto a sample board through a dispenser, a pipettor is used for transferring the sample board onto a chip sample application instrument, and the mass spectrum and relatedinformation of the nucleic acid are obtained through laser sampling of a mass spectrometer, so that the nucleic acid is analyzed rapidly, directly and continuously. The automated instrument is high-precision in controlling the volume of dispensed liquor, high-cleanliness in controlling the quality of the dispensed liquor and high-efficiency in meeting sample application requirements of large-batch samples; meanwhile, the samples are uniformly distributed under the control of a computer program, volume errors and possible foreign pollution caused by manual operation are avoided, and the speed and efficiency in sample application are increased at the same time.