As an important part of the quantum logic devices, quantum latches have great significance in the field of quantum computers. According to the quantum latch logic functions and relationship between the input and output of quantum latches, auxiliary bits was introduced to solve the problems of digital circuit feedback and realize the latch function of keeping data state. Five different quantum latches were designed and constructed and then the quantum routes for optimization were modified. Such quantum latches can be used as general and scalable basic latch functional unit in the construction of quantum computers.