Abstract: In the testing of the miniature magnetic sector mass spectrometer,the upper-computer software sends indirect instructions to lower-computer to achieve scanning control,the ions current collection,processing,storage and analysis.This paper uses the method of object oriented program design,in the vc++ 6.0 programming environment for mass spectrometer upper-computer software design and implementation.The upper-computer software communicates with lower-computer through the CAN bus,to achieve controlling lower-computer and data acquisition.The mass spectrometer utilizes upper-software acquisition and processing data,substitute a large amount of miscellaneous artificial treatment work of datum.It can store data in real time,reproduce and analyze data at any time,get the useful data from it,avoid the losing of the data,improve the success rate of the experiment.Through the testing results,the upper-software designs correctly and has strong engineering practicability.