A baffle plate assembly has a baffle plate comprising a back plate and a partition wall. The back plate has an inner space and is attached to the housing of the compressor. The partition wall is formed on the back plate to divide the inner space of the back plate into at least one upper guiding channel communicating with the compressing chamber in the compressor and at least one lower guiding channel communicating with the motor chamber of the compressor. Accordingly, the working fluid can be respectively led into the compressing chamber and the motor chamber of the compressor through the at least one upper guiding channel and the at least one lower guiding channel in a certain proportion. Consequently, the compressor will operate at an optimal condition.