3XMM J031820.8-663034 , first detected by ROSAT in NGC 1313 , is one of a few known transient ultraluminous X-ray sources ( ULXs ) .
In this paper , we present decades of X-ray data of this source from ROSAT , XMM-Newton , Chandra and the Neil Gehrels Swift Observatory .
We find that its X-ray emission experienced four outbursts since 1992 , with a typical recurrent time \sim 1800 days , an outburst duration \sim 240 - 300 days , and a nearly constant peak X-ray luminosity \sim 1.5 \times 10 ^ { 39 } erg/s .
The upper limit of X-ray luminosity at the quiescent state is \sim 5.6 \times 10 ^ { 36 } erg/s , and the total energy radiated during one outburst is \sim 10 ^ { 46 } erg .
The spectra at the high luminosity states can be described with an absorbed disk black-body , and the disk temperature increases with the X-ray luminosity .
We compare its outburst properties with other known transient ULXs including ESO 243-49 HLX-1 .
As its peak luminosity only marginally puts it in the category of ULXs , we also compare it with normal transient black hole binaries .
Our results suggest that the source is powered by an accreting massive stellar-mass black hole , and the outbursts are triggered by the thermal-viscous instability .