The　Haber-Bosch　process　is　the　most　widely　used　synthetic　ammonia　technology　at　present.　Since　its　invention,　it　has　provided　an　important　guarantee　for　global　food　security.　However,　the　traditional　Haber-Bosch　ammonia　synthesis　process　consumes　a　lot　of　energy　and　causes　serious　environmental　pollution.　Under　the　serious　pressure　of　energy　and　environment,　a　green,　clean,　and　sustainable　ammonia　synthesis　route　is　urgently　needed.　Electrochemical　synthesis　of　ammonia　is　a　green　and　mild　new　method　for　preparing　ammonia,　which　can　directly　convert　nitrogen　or　nitrate　into　ammonia　using　electricity　driven　by　solar,　wind,　or　water　energy,　without　greenhouse　gas　and　toxic　gas　emissions.　Herein,　the　basic　mechanism　of　the　nitrogen　reduction　reaction　(NRR)　to　ammonia　and　nitrate　reduction　reaction　(NO3-　RR)　to　ammonia　were　discussed.　The　representative　approaches　and　major　technologies,　such　as　lithium　mediated　electrolysis　and　solid　oxide　electrolysis　cell　(SOEC)　electrolysis　for　NRR,　high　activity　catalyst　and　advanced　electrochemical　device　fabrication　for　NO3-　RR　and　electrochemical　ammonia　synthesis　were　summarized.　Based　on　the　above　discussion　and　analysis,　the　main　challenges　and　development　directions　for　electrochemical　ammonia　synthesis　were　further　proposed.