Customer demand is the key of the implementation of the product supply strategies for the manufacturer. There are three different patterns: essential demand pattern, non-essential demand pattern, and semi-essential demand pattern. The product supply strategy, which is formulated by the manufacturer to individual customers under a semi-essential demand pattern, is mainly discussed here. First, two mathematical models, in which the manufacturer obtains the best profit under the two supply modes of off-invoice and unsold-item processing, are constructed in the semi-essential demand pattern. Finally, numerical examples are used to verify the model validity.