A device for mounting an LED lamp tube is provided. The device includes two mounting base, each of which includes a mounting socket, a rotary member and a connection member. The rotary member is received in a cavity defined in the mounting socket, and is rotatable with respect to the mounting socket, and remains static with respect to the mounting socket when not being rotated. The rotary member defines a pair of mounting holes for insertion of pins of the LED lamp tube thereinto. A first connection portion is formed on one end of the mounting socket. A second connection portion is formed on one end of the connection member, the second connection portion is configured for engaging with the first connection portion, to latchingly connect the connection member to the mounting socket, and retain the rotary member in the cavity of the mounting socket.