At the Hong Kong Film Awards the following year, which was affected by SARS, the film received 16 nominations and eventually won important awards such as Best Picture, Best Director, and Best Actor.

On this day in 2002, "Infernal Affairs" was released in Hong Kong, China. At the Hong Kong Film Awards ceremony that was affected by SARS the following year, the film received 16 nominations, and eventually won important awards such as Best Picture, Best Director, and Best Actor, becoming the biggest winner.

The inspiration for the film comes from John Woo 's " Face Changing ", but Mak Siu-fai believes that "swapping faces" is something that cannot happen in reality. He wants to tell a story where the two characters only change their identities and identities. There was an exchange of hearts, and in the next five years, the script of " Infernal Affairs " was born.

Infernal Affairs comes from the Buddha's saying: The body is eternal and eternal, and longevity is the great calamity in Infernal Hell. Also known as the Infinite Hell, formerly translated as "Abi Hell", it is the most painful of the eight hells in Buddhist stories, and is also the lowest level among the so-called eighteen levels of hell among the people.

When the film was released, the Hong Kong film industry was in a slump. Every Hong Kong film came out with a hit, and the box office of each film was mostly around 2 million Hong Kong dollars. 5 million is already good, but in the end "Infernal Affairs" earned 55 million in Hong Kong. box office, and was purchased by Warner Bros. at a high price for reshooting rights. It was the 2006 remake of "The Departed" directed by Martin Scorsese.

"Infernal Affairs" is the first collaboration between Andy Lau and Tony Leung since they filmed the TV series " Five Tigers Will Break " in 1991. The script of this film was produced by Andy Lau's Tianmu Company, but due to the company's lawsuit at the time, Andy took the script to Media Asia boss Lin Jianyue. During the process, Andy Lau also improved and created the script. After the filming of the film, Andy Lau participated in the editing, cutting out too many scenes of his original role as the absolute male lead, and adding scenes to Tony Leung Chiu-wai, balancing the film into a dual-lead film.

Since Shawn Yue had to act opposite the rumored rival Edison Chen , in order to avoid conflicts and embarrassment, the film company’s boss Lin Jianyue came to the filming site to supervise the filming, and the two of them also gave the boss face and showed their proper demeanor. Talking and laughing in public from time to time. During the filming process, Edison Chen's left collarbone was damaged due to friction with the spear due to repeated movements, while Shawn Yue was trapped in a secret room and punched sandbags wildly.

At the beginning of the filming of the movie, the Hong Kong police felt that the film's subject matter was sensitive and might damage the image of the police force, so they wrote to the director to request slight modifications.

Once Elva Hsiao and Tony Leung acted opposite each other. Before the director officially called to start filming, Tony Leung had already entered the scene. He stared at Elva Hsiao intently, but Elva Hsiao did not dare to meet his eyes. After filming officially started, when Elva Hsiao and Tony Leung looked into each other's eyes, she was so nervous that she almost fainted.