Abstract: In software of industry control, real-time data acquisition and control are often used.This paper probes into method of real-time data acquisition under Win 9x.Virtues and weaknesses have been showed by comparison.Using one of methods in designing a computerized logging system, it has succeeded in realization of data acquisition under Win 9x.Real-time was met and run in a good condition. Key words:data acquisition, timer, multi-thread, interrupt, VxD