Palace striker Christian Benteke, who left Anfield for Selhurst Park last summer, has netted 12 goals this season including the equaliser in the 2-2 draw against Leicester City last Saturday.
Wilfried Zaha has also contributed with the goals for the Eagles this term, with the Ivory Coast international on six strikes in the league and nine assists.
Liverpool sit in third place in the Premier League standings, but have had a hard time keeping out the goals this season although they did manage to avoid conceding when they beat West Brom 1-0 on Sunday.
With the Reds now set to host relegation-battlers Palace at Anfield this weekend, Klopp says his team must be prepared for the aerial threat that Sam Allardyce's side will pose.
"When the ball is in the air Christian is a major threat. We felt it a lot of times here," Klopp said.
"If we let them cross 50 balls it's pretty likely he will have some dangerous headers.
"But if you only concentrate on Benteke, you have (Wilfried) Zaha and (Andros) Townsend around him. That is one of the best offensive lines in the Premier League."
Liverpool have major concerns in defence ahead of the match, with Joel Matip, Ragnar Klavan and Lucas Leiva doubtful to feature against Palace because of injury. The Reds are also without midfielders Adam Lallana and Jordan Henderson.
And when asked about his side's injury issues, Klopp said on Thursday: "Muscle problems with Joe Matip, (a) little bit with Lucas Leiva. Small problem with Ragnar Klavan, could be also not enough time.
"Adam (Lallana) is back on the pitch. (He) should be involved next week in normal training.
"At this moment he [Henderson] cannot train. We have to wait."