External seeded free electron lasers (FELs) hold great advantage of emitting extremely high intensity, fully coherent, specially stable light, allowing researchers to study the structure of matter in ultra-small space and ultra-fast time scales. The light with a special transverse phase mode, especially vortex light with orbital angular momentum has been used in many scientific fields. However, the transverse mode of the FELs radiation is basically a simple gaussian mode. In this paper, the generation of the vortex light based on echo-enabled harmonic generation (EEHG) free electron laser is theoretically studied and the simulation studies are carried out according to the parameters of Shanghai Soft X-ray Free Electron Laser Facility (SXFEL). The results of three- dimensional simulation show that the EEHG type free electron laser can produce coherent vortex soft X rays with peak power up to GW magnitude.