In this study we realized multiphoton bioimaging, by utilizing a kind of fluorescent agent with aggregation induced emission (AIE) feature. The luminogen is called tetraphenylethene- triphenylphosphonium (TPETPP), and it is a highly specific mitochondria tracker. We studied its photostability under three-photon excitation, and found that even under long-term excitation, the three-photon fluorescence signals of TPETPP in the cells still kept very bright. Furthermore, under the same 1020 nm femtosecond excitation, TPETPP assisted three-photon imaging has higher spatial resolution than two-photon imaging of MitoTracker red FM (MT), which is a commercially available mitochondria imaging agent.