The incident took place in Birtaqi area of Garmser District last night.
Tamoor Shah Nazari, the district police chief said that seven policemen fallen unconscious after drinking yogurt shake in their security post.
He said then Taliban went there and martyred them.
According to Nazari, Taliban have also taken weapons and police vehicle from this post.
This is second attack of its kind in Helmand province in less than three weeks.
The first incident took place in Sar Gora area of the provincial capital Lashkargah on the night of August 16.
On that night, five policemen were made unconscious in their security post and then beheaded with a knife by Taliban.