Abstract: As economic globalization and supply chain networks have become more complex, the boundaries between cooperation and competition have become blurred. "Coopetition" has become a new business practice for many high-tech companies. Therefore, manufacturers should consider the problem that whether to purchase from a supplier with a competitive relationship, or to widen the difference between products by improving quality. The original equipment manufacturer(OEM) procurement and quality decisions in the presence of a competitive supplier with reliable supply capabilities and a non-competitive supplier with unreliable supply capabilities are studied. Three procurement models are considered, namely OEM procurement only from the competitive supplier, OEM procurement only from the non-competitive supplier and OEM dual sourcing procurement model, through theoretical and numerical simulation analysis of OEM brand effect, the competitive supplier' imitation ability and the influence of the supply capacity of the non-competitive supplier on decision variables and profits. It is found that the product quality of OEM decision-making improves, with the increase of its own brand effect, and the degree of competition of the competitive supplier could be reduced by the brand effect. Dual sourcing procurement is the best procurement strategy for OEM. When the imitating ability of the competitive supplier is small, the product quality of OEM decision-making improves as the imitating ability of the competitive supplier increases. When the imitating ability of the competitive supplier is large, the enhancement of its imitating ability will cause the OEM to reduce the quality of the product. The non-competitive supplier's ability to increase raw material supply does not necessarily bring higher profits for itself.

Key words: coopetition supply chain, brand effect, product quality, imitation ability