The Olympic, European and Commonwealth Games champion beat Laopeam, 32, in a strong showing to claim her first World Championship gold.
After a cagey, cautious opening period, Adams connected with several good combinations in the second round to put her opponent on the back foot.
The third round saw the Thai attempt to take the fight to her opponent, but Adams held firm through the fourth and final round to claim victory on points.
Adams defeated local representative Zhaina Shekerbekova in the semi-finals with a unanimous verdict.
A delighted Adams said after the fight: “I came here to win the gold so to leave as World champion is absolutely brilliant and one of the highpoints of my career.
“To finally become World Champion after losing out in three previous finals is very satisfying and shows that if you stick to your goals and work hard you can achieve them in the end.
“Winning this means I have now won every major title and I am really happy to complete the career grand slam of being Olympic, European, European Games, Commonwealth and World champion.
“The tournament has been great preparation for the Olympics and I am now really looking forward to the Games and defending my title in Rio when I hope to become a two-time Olympic champion.
“I would like to thank the coaches, the team at GB Boxing and everyone back home for their support including my sponsors and particularly the National Lottery and UK Sport.”
Adams had previously contested the World Championship finals in 2008, 2010 and 2012 but came away with silver on each occasion.
Her win makes Adams only the third Briton in history to win a World Championship, after Frankie Gavin who secured the men’s lightweight crown in Chicago in 2007, and team-mate Savannah Marshall who won the women’s middleweight title in Qinhuangdao in 2012.
Adams’ victory was the highpoint of another successful week for Great Britain’s female boxers which saw Savannah Marshall qualify for the Olympic Games in Rio and secure a bronze medal in the middleweight category.
The medals for Marshall and Adams mean women from GB Boxing have won 16 medals at eight major tournaments since the establishment of a female boxing team in 2010.