In this paper, we are going to show how to build up agentoriented Public Key Infrastructure(PKI) from SPKI/SDSI and X.509 standards. A variety of delegation mechanisms for agents will be demonstrated under this agent-oriented PKI. The mechanisms include: chain-ruled, threshold, and conditional. The lack of agent security management standards did not allow us to do the agent trust and delegation in legalized manner so we proposed several new communicative acts to satisfy our agent delegation management. Finally, we briefly show how to implement these agent communication language and inner content language in XML and XML/RDF.