To label the CD4+ T cells F-actin，the lifeact gene was synthesized and cloned into vector pEGFP-C1,CD4+T cells were then transfected with pEGFP-C1-Lifeact plasmid and imaged by the real time super-resolution 3D-SIM fluorescence microscopy.The results showed that F-actin is distributed around the cellular membrane with steady state of depolymerization and polymerization.It was indicated that the spatial resolution of the fine SIM imaging of F-actin was two to four times higher than the wide field fluorescence microscope imaging.