Both religions originated in Asia, and both stress proper conduct over believe in God(s). There are however a number of differences.
One difference is that Buddhism does not include a belief in God, and Confucianism does. Additionally, in Confucianism, and not in Buddhism, there is the cult of ancestors.
The goal of Buddlism is to escape life (suffering). Confucianism stresses a hierarchical structure in society, as a way of ensuring a good, structures society. Confucialism is in a way a way of structuring life, society.
In Buddhism one wants to escape the circle of life, and in Confucianism the aspirations for life after death are to be worshiped by the descendants.
There is a number of further difference such as status of women (inferior in confucianism, equal in Buddhism). Also confucianists include elements of Buddhism, but Buddhists practice their religion exclusively.