Nowadays a new businesses form, online business occurred, which helps companies to improve their working efficiency in managing risks and allocating resources. Relationship and network are essential for understanding online business, which can help firms to reduce costs by outsourcing, and to increase efficiency by sharing information with cooperators. That leads to the purpose of this study, is to investigate how do the relationship and network between firms influence the cooperation of product developing and server operating companies within online business. In order to study this topic, the concepts from IMP group of characteristics of relationship, relationship development stages and the model of managing in networks are applied. Furthermore qualitative research method was employed for interviewing five companies in two types: 1) product developing companies 2) server operating companies.     The relationship and network are perceived by interviewed companies are dynamic, fast changing and high technology focused. To cope with this phenomenon, most of companies choose to put their efforts on developing products and advancing technology rather than communicating with partners. In conclusion, the cooperation between firms in online business is influenced by fast changing and short-term relationships, high competition and the risk of plagiarism, which leads to competition focus in their business.