Lamichhane has been the face of cricket in Nepal, being the only player from the Himalayan country to feature in prominent Twenty20 leagues across the world.
He was suspended as Nepal captain last month and left the Caribbean Premier League after being accused of raping a teenager. He has denied any wrongdoing.
"We took him into our custody, carried out a medical check-up on him at a hospital and investigations will continue," Dinesh Mainali, a Kathmandu Police spokesman, told Reuters.
Lamichhane, wearing a white hoodie and black cap, made no comments to the media after being detained at Kathmandu airport.
In a Facebook post before he was detained, the cricketer said he would "fully cooperate in all stages of the investigation" and vowed to "prove my innocence".
"I know I am facing a difficult time of conspiracy and wrongful allegation and the ramification of its effect is something unimaginable," he wrote.
"I will soon seek legal support against wrongful prosecution and allegation made against me and I am sure I will get the justice and will return to the cricket ground soon..."
Nepal failed to qualify for the upcoming Twenty20 World Cup.
