In the industrial marketing literature, the effects of relationship quality on commercial partners, especially industrial suppliers and buyers, has been investigated from different aspects. Positive variables affecting the relationship, such as trust, commitment, satisfaction, communications and intention to long-term relationships, as well as negative variables, such as opportunism and conflict, have been considered. By identifying these variables, reinforcing positive variables, decreasing the effects of negative variables, and developing long-term relationships, a supplier can acquire valuable results. This research employs descriptive correlation methodology, whit a sample of 79 industrial crane buyer firms; a conceptual plan was examined by structural equation test and PLS software. Research findings indicate that suppliers can attract satisfaction and trust from buyers with maintaining and improving product properties and decreasing opportunism and conflict. Industrial suppliers also can enhance relationship quality by focusing on commitment, which reinforces loyalty and intention for long-term relationship.