A method for continuous preparation of high bulk density methionine crystals, comprising the following steps: mixing a hydrolysate solution containing potassium methionine obtained from a reaction of 5-(β-methylmercaptoethyl)hydantoin and a potassium carbonate solution with an external circulation material from a Draft Tube Baffle (DTB) neutralization crystallizer having a gas phase neutralization section to form a mixture material; the mixture material entering a liquid distributor of a neutralization region (A) in an upper part of the crystallizer after being cooled and being sprayed in the form of liquid droplets or trickles to gas-liquid contact area to carry out a neutralization reaction with carbon dioxide gas so that obtaining a neutralization solution containing methionine; making the neutralization solution naturally fall into a crystallization region in the lower part of the crystallizer to form crystals in the crystallization region, and then making the crystals having larger particle diameters deposit into an elutriation leg in a deposition area in the middle part of the crystallization region; feeding the methionine crystals in the elutriation leg through a crystal mush pump into a rotary drum filter to be subjected to separation, washing and drying to obtain methionine products; wherein the external circulation material is initially a saturated methionine solution; wherein the DTB neutralization crystallizer having a gas phase neutralization section has a gas phase space at an upper part, and a liquid distributor and a gas distributor are provided so that the liquid as a dispersed phase is subjected to a gas-liquid neutralization reaction in a carbon dioxide gas as a continuous phase; and wherein bulk density of the high bulk density methionine crystals is at least 800kg/m3. mixing a hydrolysate solution containing potassium methionine obtained from a reaction of 5-(β-methylmercaptoethyl)hydantoin and a potassium carbonate solution with an external circulation material from a Draft Tube Baffle (DTB) neutralization crystallizer having a gas phase neutralization section to form a mixture material; the mixture material entering a liquid distributor of a neutralization region (A) in an upper part of the crystallizer after being cooled and being sprayed in the form of liquid droplets or trickles to gas-liquid contact area to carry out a neutralization reaction with carbon dioxide gas so that obtaining a neutralization solution containing methionine; making the neutralization solution naturally fall into a crystallization region in the lower part of the crystallizer to form crystals in the crystallization region, and then making the crystals having larger particle diameters deposit into an elutriation leg in a deposition area in the middle part of the crystallization region; feeding the methionine crystals in the elutriation leg through a crystal mush pump into a rotary drum filter to be subjected to separation, washing and drying to obtain methionine products; wherein the external circulation material is initially a saturated methionine solution; wherein the DTB neutralization crystallizer having a gas phase neutralization section has a gas phase space at an upper part, and a liquid distributor and a gas distributor are provided so that the liquid as a dispersed phase is subjected to a gas-liquid neutralization reaction in a carbon dioxide gas as a continuous phase; and wherein bulk density of the high bulk density methionine crystals is at least 800kg/m3. <EOS>