Future global information networks are often described as rich collaborative environments in which intelligent automated services enable enterprises to dynamically discover, interact and do business with each other. To be competitive in the new "e-economy" it is vital that researchers and industry alike are able to exploit emerging technologies that will form the basis of tomorrow's global information networks and act as the worldwide infrastructure for automated commerce. Multi-agents (MA) systems are types of distributed systems which consist of autonomous agents, which routinely use rich social interaction with other agents to complete tasks they have been assigned. Appling intelligent agents or multi-agent systems in e-commerce can be considered as multi-agent based e-commerce, which has been among the most rapidly growing areas of research and development in information technology in the last few years. The underlying objective of the thesis is build a new adaptive trust andreputation model for multiagents negotiation for e-contracting in order to reduce uncertainty about different agents dealing with each other in e-commerce environment.