It was the fourth successive Group A defeat for Great Britain, who had already lost to Montenegro, Russia and Brazil in their opening three matches.
They had hopes of beating the African champions, having done so in the Copper Box in November's test event, but Angola have improved considerably.
Despite nine-goal Marie Gerbron top-scoring, sloppy play in the attacking third cost Team GB, with too many missed chances and handling errors.
Despite a solid start keeping the deficit down to 5-4 after the opening 10 minutes, Britain could not make it pay at the other end due to several misplaced passes and glaring misses.
Angola scored five of the next six goals to open up what was looking like an already unassailable five-goal lead after 18 minutes.
Lyn Byl, Team GB's top scorer in the tournament, stopped the rot with a nice turn and throw and Gerbron added a penalty to keep her side in it.
Britain managed three unanswered goals to bring the gap down to 14-10 at the break and for the first time in the competition the women came out for the second half playing for something other than pride.
Kelsi Fairbrother and two Britt Goodwin goals raised the roof as they brought their deficit back to three.
Angola continued to keep Team GB at arm's length, though, and four of the next five goals stretched that lead to six as they remained in control.
After that the Africans flexed their muscles, snuffing out GB's challenge courtesy of four successive goals midway through the second period.