Bellingham has been in superb form since joining Real Madrid in the close season transfer window, scoring 10 goals in his first 10 starts for his new team in all competitions.
"He can be the difference," Trippier told reporters. "At such a young age, with the maturity, the quality and the aggression he's got, he's frightening. It's not a surprise at all, the standards that he's set in Madrid.
"You can see he's playing with freedom and the players around him are going to make him even better. The scary thing is he's only 20 years old."
Trippier added that the England side had made "massive steps" since the 2018 World Cup, saying: "We lost in the Euros final but the most important thing is we're progressing and doing very well.
"We've got goals from all over the pitch and Jude, Madders (James Maddison), Bukayo (Saka), Phil (Foden) are still young but can all change games in certain moments."
Trippier also defended team-mate Jordan Henderson, who was booed by England fans during Friday's 1-0 friendly win over Australia after joining Saudi Arabian club Al-Ettifaq earlier this year.
"For us as players, we stick together," Trippier said.
"I see Hendo on a daily basis. He is an unbelievable character, he's a leader – what he does for the team, playing or not playing.
"He's an unbelievable person to have in the dressing room. He makes sure everyone trains properly. He sets standards."
England face Italy on Tuesday at the Wembley Stadium.
