Abstract: Based on the pilot sub-critical fluid extraction device, through the modification of metal filter basket for extraction to the multichannel asymmetric microporous composite ceramic membrane filter element, the increase of extraction solvent recovery system and the installation and adjustment of relevant important parts, the qualitative and quantitative analysis of fatty acids and volatile active components in plant oil can be realized accurately, and the system pressure was fluctuated within 1.55±0.05 Mpa and was stable and controllable, the extraction efficiency of plant oil was increased to more than 95%, the average extraction time was shortened by about 75%. The average recovery was about 93%, the effective recovery and utilization of extraction solvent, the energy conservation and emissions reduction can also be realized. Thus, the escalation and modification of the multichannel recyclable mode instrument is realized, and the purpose of increasing the extraction capacity of the instrument is achieved.