In 2003, Boy'z entered the entertainment industry under the banner of "Male Twins". At that time, the members were Kenny Kwan (Kenny) and Steven Cheung (Steven). In February 2005, Kwan Zhibin made personal development and quit Boy'z. Therefore, the second generation

Boy'z has added new member Mai Zihao (Dennis).

In June 2006, Boy'z added a new member, William Chan, and became a trio. They changed their name to Sun Boy'z, showing off a new image, and Steven became the leader of the group.

In April 2008, William Chan officially announced his personal development and his withdrawal from Sun Boy'z, becoming another member to withdraw from Sun Boy'z after Kwan Chi Bin.

In December 2008, Mai Zihao officially announced his withdrawal from the entertainment industry because he needed to go to Switzerland to study hotel management courses.