An ultrafine fiber printing system contains a moving deck having a nozzle seat that is disposed on the moving deck. A pipe is installed in the nozzle seat, and a nozzle is disposed at the bottom end of the pipe. The upper portion and the lower portion of the pipe are combined with a heat dissipating unit and a heater respectively. The top end of the pipe is connected to a feed tube having an outer end connected with a thread squeezer. A printing platform is disposed around the moving deck. The nozzle is connected to a static electricity supply, and the fiber carrier is grounded. An electric field is formed between the nozzle and the fiber carrier. The droplets exported from the nozzle are stretched into ultrafine fibers to form a patterned fabric or product.