The invention discloses an all-digital AIS (Automatic Identification System) receiver system based on radio frequency direct sampling, which comprises a receiving antenna, an analog front end, an analog/digital converter, a field programmable gate array (FPGA) chip, a USB transmission controller, a temperature compensation crystal oscillator, a phase-locked loop (PLL) clock synthesizer, a GPS receiver and a host. The all-digital AIS receiver system adopts a mode of radio frequency direct sampling, so that active devices such as an analog mixer, a phase-locked loop frequency synthesizer, a filter and a baseband demodulation chip are saved, and influences brought about by noises of an analog device are reduced; and signal down-conversion is completed in a digital domain by using the FPGA chip, and a problem of nonlinear distortion brought about by the analog mixer is avoided; and the system is simple and clear in structure, small in hardware scale, flexible in configuration and good in performance, and the furthest distance of AIS message reception can reach up to 50km.